For the investigators seeking to identify child pornography victims, every little bit of information – from the designer of the clothing worn in the pictures to the type of wallpaper in the background – helps, law enforcement experts told ABCNEWS.com.
"We look at the house and the building and determine whether [the tape was filmed] outside," said Detective Constable Bill McGarry, an image analyst at the child exploitation section of the sex crimes unit at the Toronto Police Department. "We look for anything that will point us to a geographical location and also try isolate objects in the background – furniture, bedding, clothing – things that we can trace to certain manufacturers. It's a lead that can make all the difference."
These clues, said McGarry, are vital to cases like the one in Nye County, Nev., where authorities are searching for the second girl seen on a videotape that depicts a man performing sex acts on a young girl. The tape was turned over to authorities by Darren Tuck, who said he found the tape in the desert and has since been arrested on charges of possession and promoting child pornography.
While one girl seen on the tape has been located and is safe, according to the Nye County Sheriff's Office, the second, said to be either 4 or 5 years old when the tape was made several years ago, hasn't been identified. Her name is believed to be Madison, police said, based on what they heard on the tape.
[UPDATE: Police said late Friday, Sept. 28, that the younger girl in the videotape was found and "safe."]
At a press conference Friday, the Nye County sheriff's office identified Chester Arthur Stiles, 34, as a "person of interest" in the case. Stiles is wanted on both state and federal warrants for sexual assault and lewdness with a minor.
'We Look at Every Clue'
Less than 1 percent of children who appear in sex tapes are found each year, according to Interpol statistics. That means sex crime investigators are often left with no choice other than to dig deeper into the minute details caught on tape in hopes of pinpointing both the victimized children and their assailants.
With so many videos to sift through, deciphering the country of origin can be a challenge in and of itself. McGarry will meet with a group of international investigators on a secure Web site to trade information about particular videos and victims. Once the location of the video is determined, an investigator from that region will take over the case. Often, though, investigators will collaborate no matter where they are located to close a particular case.
McGarry, who said he has been in contact with the investigators handling the Nevada case, said that determining whether the video of the two girls was taped at the same time or cut and edited together will be helpful to finding the victim.
VHS tapes, unlike video streamed over the Internet or recorded on DVDs, have less of the embedded data that can tell investigators the date the video was shot, said McGarry. If the tape wasn't edited, the fact that the investigators already found one of the victims could be a huge help to finding the second missing girl.
But without much detail coming from the VHS itself, investigators use other techniques to look for clues.
"We look at the videotape and you've got to slow it down and take the people out if it so that you're not just concentrating on the act that's happening but on everything going on around it," said Detective Janet Sobotka, who works with McGarry at the child exploitations unit in Toronto. "And if worse comes to worse, you put it on the news to see if anyone can recognize [the image]."
Sometimes the public's knowledge of a particular place or person can be investigators' key clue to find a victim or an offender, Sobotka said, further emphasizing that media exposure can be a great help in child porn cases.
Nevada authorities have now released still images of the missing girl, the person of interest and the man who turned the tape over to authorities. Media outlets have published these photographs, along with tip line telephone numbers, in case viewers can help the investigators identify the victim and her offender.
During the press conference, Nye County authorities expressed their gratitude to the American public, many of whom have already "inundated" the police department with tips.
Determining the manufacturer of the material items caught on tape, said McGarry, is another method that often leads investigators directly to the victim. McGarry remembers once case he worked on was able to locate a young female victim after discovering the dress she was seen wearing in the video was a school uniform. McGarry then contacted the uniform manufacturer who told him which schools ordered the clothing.
Similarly, Nevada authorities have tracked down the manufacturer of the lingerie worn by the missing girl to a manufacturer in North Carolina.
How the Investigators Cope
When your job involves pouring over thousands of sexually explicit child pornography tapes for weeks on end and often making little headway, the toll it takes on your mental state, as well as your personal life, can be difficult, investigators told ABCNEWS.com.
"We all have the responsibility to look after each other," said Sgt. Kim Scanlan, who oversees 15 investigators in the child exploitation unit in Toronto. "We try to do the occasional outing to make arrangements to go golfing or do something fun so we can kind of break the tension after a long session of viewing a lot of children porn. It breaks up the tension and gets people to think about something else."
For McGarry, who has a wife and children of his own, the satisfaction of finding a victimized child is worth the grueling hours spent viewing the tapes.
"We keep in mind that the ultimate goal is to find the children," said McGarry, who added that he has become "hyper-vigilant" of his own children. "If you can keep that in perspective it keeps you going and there is great satisfaction when you actually find a child."
Sex crime investigators are required to get psychological evaluations, and meet with therapists who evaluate how they are coping with their jobs every six months.
When asked what the worst part of her job is, Sobotka, who no longer watches as many tapes as she used to thanks to a promotion, answered "frustration."
"There are certain [children] that stick with you," said Sobotka. "There are certain images or certain children that you think about. It's frustrating not being able to help each and every one of them and [not being able] to prevent it from happening to other children."