Sometimes trivial enough clues to solve a case.

In 2012, a photo taken on vacation with a woman and a child showing a freshly caught fish has become the main track in an investigation into a case of child pornography.
Found in the midst of an abundance of illegal explicit material, the photo has directed officers to a campsite in Richville, Minnesota, and has helped to save the victim and order the suspect in December 2012.
But first, investigators had to figure out where it had been scatatta the photo.
To do that, they cut away the fish, cleaned the image and have it sent to Cornell University for identification, said by phone on Motherboard Jim Cole, head of the National Program for Victim Identification ICE (Immigration and Customs Enforcement), an agency that is part of the DHS (Department of Homeland Security).
The university has been able to determine the species of the fish, which is located in a particular region.
The officers then removed the suspect and the victim from the picture, Cole said, and handed out the image of the place to someone who is advertising for the camping sites, as long as someone has not recognized an exact location.
When they arrived the officers, the same picture was hanging on the office wall of the camp, he specified Cole.
"It's all about making the smaller the haystack to find the needle," he said.
This is just one example of how DHS and other teams around the world use tools for manipulating images, videos and audio tracks to solve crimes involving child pornography.
The DHS has found during this investigation into child pornography, and an initial examination does not contain information useful for its identification.
The NCMEC (National Center of Missing and Exploited Children), a 'not-for-profit organization that works with the police, has reviewed an average of 500,000 files a week in 2016, according to the statement by a spokesman.
This "incredible amount of data," as described by Cole, was in part collected during the investigation, in part sent by Internet providers and telecommunications operators, partly by private citizens blown.
Obviously, the Cole job forced him to look at many of these terrifying images.
Cole, as well as others, have become in a sense less susceptible to this content, but "I still see materials that leave me upset," he said.
The first step after receiving a picture is whether the victim has already been identified, this is possible by comparing the hashes or encrypted track of files.
"This method is not reliable at 100 percent, though," said Cole.
In fact, child sexual abuse imagery could be passed from person to person thousands of times, and different versions may have been uploaded to various sharing sites.
If a pixel is different, a piece of metadata has been changed, or possibly the file has been compressed in a different way, and the hashes do not match.
Instead, Cole prefers to use Photo DNA, a Microsoft tool that creates a "fingerprint" based on the image, which then allows the police to compare it to similar-files possibly just those examples that have been scaled or manipulated in some way -and successfully determine if they match or not.
If the victim has not been identified before, the agents charge the material on the image database of the 'International Child Sexual Exploitation of INTERPOL.
But with a little 'work, it could be deduced from a man's sweatshirt logo in the picture.
Finding a logo in an image may solve the entire case.
When it comes to scour a photo or video itself to find some useful clue, Cole uses a myriad of different programs, depending on the stage they are in the investigation.
To start, there Analyze of which Cole says is useful to see the different parts of the file in an intuitive way.
It is here, Cole can easily figure out which pictures could be of value to the investigation, and passes them on Photoshop to improve them and make them clearer.
There is also Adobe Premiere for video and Adobe Audition for audio-file programs that a person who uses the computer normally know.
The products developed by other similar houses are probably less known, such as Amped Five, a video editing suite, or Forensics Program Image Analysis System (FIAS).
"Photoshop is a bit 'the workhorse," said Cole.
Cole has a close relationship with Adobe: he happened to suggest adding features to the program and has been given priority access to the new tools.
"What we do is break down completely the picture.
I look at each factor, all elements present, "he added.
Not only the content but also the EXIF data that could reveal which camera was used.
When images are from unknown sources on the Internet, even a bottle of pills in a corner in the background can provide a starting point for investigation.
In a pair of images on two different victims, the suspect was wearing a gray T-shirt with a dark blue logo on the left chest almost illegible, Cole said.
In order to reconstruct the text, Cole raised exposure, but it was not enough.
Then reduced blur, it applied a filter to sharpen the contours, and has used a tool to manipulate the color gradient.
Technical level after a technical level, until they are able to identify the logo as a company that deals with plumbing and electrical systems in Maryland.
The suspect turned out to be a former employee of the company, and agents are able to save four victims from imminent abuse.
In other cases they had to acknowledge the details written on the pill bottles, or highlight the logo of a fast-food on two glasses of soda in the background image.
But every situation is different, said Cole.
Some cases can be resolved in a few hours, others are still open after a decade.
Some suspects using the same tools that Cole uses to cover his tracks-or what Cole calls "techniques to impede the recognition of victims."
On certain Web forum dark, the child pornographers exchange advice on how best to use the most common software.
"They are tutorials on how to use Premiere Pro and tracking to obscure his face [in the video]," said Cole.
And it is in the dark web that most cases originate Cole.
In fact, Cole has had to deal with images of Playpen, a pornography site that iFBI seized in February 2015, and then used to infect computers with a program of who was suspected of child pornography.
"Every time I had seen it all, something comes along that makes me change my mind."

From Vice