Gray Alan Combs Jr. was shot to death after he threatened Fairfax County police with a sword last month.
Willis E. Coley, 27, of Alexandria, hanged himself in August.
George N. Kiriacon, 50, committed suicide in a truck in New Carrollton.
The common thread among these three men is that all had been charged with child sex crimes shortly before their violent and/or self-destructive actions.
The FBI and the U.S. Marshals Service have documented a disturbing trend in which those confronted with charges of child abuse react by attacking others or harming themselves.
Law enforcement authorities say they are seeing more incidents as police have increased efforts to apprehend those who produce, distribute and view child porn. Over the past 20 years, federal child sex pornography cases have increased 330 percent -- from 481 in 1999 to 2,069 in 2009.
Ronald Hosko, special agent in charge of the FBI Washington Field Office's Criminal Division, said he noticed the phenomenon in 2008, as an inspector for the FBI's Inspection Division, where he reviewed deadly shooting incidents around the country. Subjects pulled a weapon as FBI agents knocked on their doors to ask questions or execute a search warrant, putting the lives of themselves, family members and the agents in danger.
"It's a life-changing event," Hosko said. "At that moment, their world is collapsed around them. And they think the only way out is at the point of a gun."
A new FBI study found that in 106 cases where an individual committed suicide after he became aware that he was being investigated, 54 killed themselves within 30 days of being contacted by law enforcement. About half of the sample did not have a prior criminal history.
Combs was wanted for producing child pornography. Coley was two weeks away from being indicted on federal child pornography charges. Kiriacon was found dead a day after the public disclosure that a 15-year-old boy had accused him of abuse.
"This is a different type of suicide. This is a suicide motivated not so much by depression but by desperation," said Dr. Michael Bourke, chief psychologist with the U.S. Marshals Service's Behavioral Analysis Unit. Bourke had been studying this issue after the passage of the Adam Walsh Child Protection and Safety Act in 2006, which authorized the Marshals Service to track down sex offenders who are unregistered or have violated the terms of their registration.
Many of the suspects seemed to have led normal, responsible lives, experts said. Suddenly, they're facing the shame of being exposed, being ostracized by their family and friends, they're looking at spending a long time behind bars, where it's commonly held that the most reviled inmates are those serving time for child sex abuse.
A 2005 study in the United Kingdom found child sex offenders who had no other criminal records were 183 times more likely to commit suicide than the general population.
The FBI and the U.S. marshals are refining their tactics for approaching subjects, such as determining if the target has a gun and using a force team to make arrests or serve warrants.