Category Archives: Future Forensics
Forensics at the cutting edge and beyond
Forensic audio analysis has been around long before the Watergate tapes and continues to make advances. But a monumental leap forward occurred about a decade ago right here in Colorado. You see, one of the foundational elements of any analysis is that of authentication. Edited and doctored recordings should always be considered when reviewing audio evidence. It’s more than just verifying the identity of the source. The source being a person or activity like a gunshot, car horn, or mechanical device. It’s also about verifying the date and time of the recording. Was it made just before the commission of the crime or a year earlier? Sometimes the words said are not as important as when they were uttered. It is the when that helps detectives put things in context. It turns out that within virtually every audio recording there is a silent witness.
There is something called the mains frequency. Inaudible to our ears it is a persistent hum generated by our electrical grid. Amplify the sound and you’ll hear a metallic buzz. Researcher Dr. Catalan Rigoras discovered that this hum fluctuates as the load on the power grid goes up and down. Think of it as a melody of notes arranged in an ever changing symphony. Since the load on the electrical grid is constantly changing, so too is the frequency of the hum. So forensic audio specialists and other researchers have embarked on am ambitious project to record this hum every second of every day and cataloging the signatures in a searchable database. It’s called Electric Network Frequency (ENF) analysis and they’ve been doing it for years. So if an audio recording is made anywhere near an electrical source it will record the hum as well. It can be an electrical outlet, a lamp, computer, anything. The distinctive hum signature acts like a time stamp or watermark. It is unique to that moment in time. The longer the recording the more easily it can be authenticated.
The hum is unique to the power grid so it can get a little more tricky in countries with multiple grids in service. But if a single grid is in use the value of the analysis increases dramatically. Say for instance that someone cuts and splices pieces of audio together…the hum signature won’t match. There will be gaps in the hum when compared to the source hum in the database. What happens when two different audio tracks are combined to make a fake original? There will be two hum frequencies in the background. So unless your recording is made in the desert or the middle of the forest the recording will likely contain the distinctive hum in the background. You might want to consider using this technology in your novel. Whether your character is talking on a cell phone or being recorded on a surveillance system the hum will be there. The key is to use some kind of doctored recording. Your protagonist can then do the ENF analysis to show that the recording has been tampered with (or is original). Either way its a really cool technology.
If you haven’t had a chance to see the latest Bond film Skyfall I highly recommend it. If you have seen it then you’re familiar with the concept of a biometric gun (also called a “smart gun”). The idea has been around for a while but, essentially, it’s a weapon that requires a biometric (finger/palm print) scan and match from the owner in order for it to fire (other concepts include RFID chips and magnetic release). This is supposed to prevent another person from firing the gun and the idea has run the rounds in the gun control circles. It’s a swell idea on paper but, in real life it’s much more problematic. Since it appears in a mega-blockbuster I thought you might want to keep a few things in mind should you choose to include a biometric gun in your next novel.
For law abiding citizens, a gun is a tool for self defense (sport too but that’s another topic for another day). When using a gun for self defense, simplicity of operation is preferred. The more complicated the system the more likely there will be a failure. All of us can conjure up images (from movies or television) of a crime victim grabbing a gun at the last possible second and shooting the bad guy. That may not be possible with a biometric gun due to a number of factors which I will separate into electronic, environmental, and situational categories.
First the electronics. Basically you have a digital scanner that reads the friction ridge skin pattern and compares it to the image on file. Then it has to determine a “match” before engaging the mechanical side of the gun to allow it to function. How long does this process take? How about in freezing weather? After being submerged? We’ve all had our laptop “freeze” up on us. It’s annoying but, we’re not fighting for our lives. Presumably the biometric gun operates with a battery of some type. Batteries can drain quickly in cold weather (ask any CSI about using a camera in a blizzard) and fail completely when wet. There are also concerns about impact damage. If the gun drops to the ground will the scanner crack? Will there be internal damage to the circuitry? When your life is at stake every second counts and you need a dependable mechanical weapon.
Aside form the electronics there are serious concerns about the “environment”. A biometric weapon requires a “clean” scan of the finger/palm print. Anything that interferes with the scanning will prevent the weapon from being fired. That means you can’t wear gloves (so much for cold weather use). Violent encounters/attacks also may result in bloodshed. If your hands are bloody then you can’t use the gun. Same goes for mud/dirt, grease, clothing, even water (firing underwater) may be problematic. One also presumes you have to have a flat even contact between your gun and skin which isn’t always possible. Hands can get cut open in a fight (defensive wounds) and the damaged friction ridge skin may not be recognized by the scanner. When you’re in a fight for your life you can get bloody, muddy, etc. and a finicky gun may cost you your life.
Lastly there are situational considerations. Imagine you’re in a public place when a bad guy comes in shooting. You get hit and go down injured. Your gun falls from your hand and a stranger picks it up as the bad guy advances on you. The stranger points your biometric gun at the bad guy, determined to save your life and his, pulls the trigger and…nothing. Well, not nothing. Presumably you’ll both be shot in a few seconds but you get my point. What if the guy that goes down is a police officer and you’re the by stander? Most likely the biometric gun won’t be “coded” to other friends and family and certainly not to a stranger yet, those may be the very people in a position to save your life or that of another.
So if you plan on using a biometric gun in your novel keep some of these things in mind. Gunfights are usually over in a few seconds. Of course, any one of these issues can add tension and danger to your plot line so feel free to use them. I can see your heroine trying to tear off her gloves as the rapist chases her through the park at midnight. Will she get them off before he catches her? Of course my heroine Sarah Richards will have a Glock so it won’t be an issue for her but, it might be an interesting challenge for your characters.
Here is an interesting story and video about a revolutionary bullet being designed like a cruise missile. When the cartridge is fired the bullet sprouts fins which control it’s flight path to the target. I doubt police will have to deal with this technology anytime soon but it opens up some interesting ideas for a science fiction crime story. The current technology is cool enough but what if your bullet actually “scented” the target like a bloodhound? I’ve written about the amazing capacity of bloodhounds in tracking human scent here and here. But what if a bullet could “scoop up” and analyze scent as a means of finding a target? Bloodhounds do it and scientists have used instruments for high volume air sample screening in atmospheric and environmental studies for years. By analyzing scent could a bullet be programmed to follow a person’s scnet or DNA which is constantly being shed in the form of skin cells. Could you literally pick a person out of a crowd?
Taking it one step further (and this is way out there but we’re talking science fiction) what if a bullet could be programmed to ignore “friendly” targets? That population of “friendlies” may be as small as family members or as large as a military division. Of course, a bullet can’t stop in mid air (or can it) and course corrections at 1100 ft/sec become increasingly difficult if not impossible as the range to target decreases but again, we’re talking fiction. This technology might be something to consider using in your science fiction novel under certain circumstances where you wouldn’t run into certain problems like crowds of people.
Another consideration is the purpose of the projectile. Maybe in your story it is designed for “tagging” or less-lethal incapacitation than it is for killing. In any event, I thought it was interesting and it got my mental gears engaged.
This is really cool technology that has great potential for our military and police, but it also has the potential to one day aid the criminal. The ADAPTIV technology employs interlocking “plates” that use surrounding imaging to project a false “picture” to everyone around it. For example, the camera sensors may take a picture of the environment behind the vehicle and project that image on the opposite side thereby rendering the vehicle ”invisible” even to the naked eye. Right now these imaging plates are pretty distinctive and look like large reptilian scales but as the imaging improves and the scales get smaller it may be indistinguishable from other materials. The great news for fiction writers (especially sci-fi or futuristic mystery) is that you don’t have to wait for the technology to catch up.
Imagine a team of bank robbers who flee the scene in an adaptive camouflage vehicle. The police take chase and are looking for a red colored sedan. With the push of a button the sedan could literally disappear, change shape, or change color. If you really wanted to push the technology envelope imagine if the windows of the vehicle projected the image of an elderly couple or a soccer mom instead of the four heavily armed robbers to any passer-by.
The technology wouldn’t be limited to just vehicles either. You could hide a safe house, room in a warehouse, or even certain items. Imagine the cops busting down the door to a drug house and the bad guys being able to hide their drugs in plain sight. They could also hide weapons, computers, doorways, or any number of incriminating items. The only way a CSI could detect the items would be to disrupt the imaging device. That might be through the use of a low-yield electromagnetic pulse or similar instrument (which I’m not sure even exist but that’s why they call it fiction right?) Play around with some ideas and see where they take you!
Apparently the answer is YES! Following a recent military plane crash in Chile, authorities used Apple’s Find My iPhone App to locate the position of the crash and the bodies of the victims after their plane plunged in the ocean. Amazingly, the phone components survived what the Chilean Military classified as a high fragmentation impact off the coast. None of the recovered plane fragments found so far are over 50cm in size! GPS based hardware and software are becoming more popular by the day. Everything from phones, cars, wrist watches, even pet trackers utilize this advanced technology.
This brings up some interesting issues for your novel. Your characters may be tracked depending on the gadgets they are carrying. This may be something you want or need to consider (depending on whether or not you want them found). I have never conducted any studies on the survivability (time and function) of a buried electronic device (but now I plan to). My guess is that devices buried (with people) in generally arid environments will survive longer than wet areas but the above case example seems to challenge even that assumption. As a writer I think you’d be safe to assume that a signal could be detected for at least several days if not longer.
Devices like these can also be used to locate suspects. Not only can they provide real-time location data they can also tell you where a suspect has been. Here are two examples of how you might use that information in your novel. Say you suspect’s cell phone is pinging off a cell tower in a remote area at midnight. If they have no reason for being there then it may indicate the location of a body dump, burial, or some other interesting activity. People don’t generally go anywhere without their cell phones and criminals are no different. In the heat of the moment the idea of leaving their cell phone behind would likely not occur to them. Another scenario would be tracking the movement of a device. If your suspect’s alibi is that he was attending a business conference in an adjoining state while his wife was murdered it would look awfully suspicious if his cell phone is hitting towers along the highway in the middle of the night going home and then returning to the conference.
However you choose to work these devices into your storyline you should always remember that they are present. As you are writing your scene ask yourself how that device might be used by the police to track it. Alternatively, could your suspect use the same technology to lead the police on a wild goose chase (like leaving it on a subway car while they get off to commit a crime and then get back on the train and retrieve it)? Just some things to think about.
Some of you know that I continue to conduct research in the forensic sciences so I thought it might be fun to share my latest paper on detecting patched bullet holes with portable x-ray units. I hope you enjoy!
Ever since Edmond Locard’s seminal work on the Analysis of Dust Traces in 1930 police have recognized the value of linking a suspect to a crime scene through the analysis of trace evidence such as hairs, fibers, soils, etc. At some point, police discovered that they could introduce special powders at certain locations at a potential crime scene that the suspect would carry away. Such was the birth of Theft Detection Powder. These fine powders were similar to fingerprint powder but were only visible under ultra-violet light. This way, the suspect could not see the powder on their hands, face, or clothing. Think of it as criminal tagging.
Police would coat the surfaces of areas that only the suspect would have access to (such as a dummy cash box, certain door handles, blank checks, etc.). When a suspect was developed or an individual was caught fleeing the scene, the police could use a simple black-light to check for the powder. If the susepct wasn’t developed for a few days or weeks the powders may have been washed from the sking but the police could still check areas like jacket pockets, ball caps, and vehicles, that aren’t cleaned often.
Soon after, another nifty invention came along. We called it Pilfa-powder but it has gone by a number of names. Like fluorescent powders, Pilfa-powder was invisible to the naked eye (although purple in large quantities) but when it comes in contact with water it turns a deep purple color. This purple staining can not be washed off and will stay on the suspects skin for weeks. Obvioulsy this makes it difficult for the offender to hide the staining from friends, family, and co-workers.
Now, researchers have developed the latest version of introduced trace evidence. This new technology uses an invisible, non-toxic chemical spray containing a unique chemical signature. A dispenser can be installed above the entry/exit door to a business and can be tripped by an employee as the suspect flees. This chemical can stay on the skin for up to six weeks and even longer on clothing. Studies in Europe show an 85% reduction in theft and a 100% conviction rate in court.
This spray could be a powerful clue in your novel. You might even consider finding it on a victim, or a ch9ild, and then have your characters trying to discern how they got it on them. There is no evidence to show that the chemical can be cross-contaminated or “rubbed off” onto a third party.