Family killers often triggered by marital, money, depression issues

He helped give his children life, cheered their first steps, chased away nightmares, coached their sports teams and served as his family's protector and provider.

Then he killed them.

Experts said Thomas Mangiantini fits the profile of a rare form of domestic homicide known as "familicide," which often cannot be easily explained and lacks clear indicators for prevention.

The Addison man fatally shot his two young sons and wife of 18 years before turning the gun on himself the morning before Thanksgiving.

Mangiantini left behind a note in which police said he was "distraught," but they have not disclosed a specific motive. He did not mention marital or financial problems, police said, though his wife lost her job last summer and his hours at work were reduced recently.

The violence comes less than six months after another suburban father, Kevin Finnerty, ignited his Arlington Heights house in a blaze that killed him, his wife and their son. Two other children survived.

Each case is unique, but some common elements, such as a psychotic break, triggered by overwhelming financial, marital or untreated depression issues, can conspire to produce a shocking crime. A homicidal parent often is motivated by the desire to alleviate their child's real or imagined suffering, experts have found.

Dr. Phillip Resnick, director of forensic psychiatry at Case Western School of Medicine in Cleveland, is widely regarded as the nation's leading expert on the topic.

His work includes testifying in the criminal trials of Marilyn Lemak, who in 1999 killed her three children in Naperville and Andrea Yates for the 2001 murders of her five children in Texas.

Resnick said these extreme family tragedies rarely are the result of an impulsive act and, in 95 percent of the cases, the man is the perpetrator. He said women are far less likely to kill their spouse after taking their children's lives.

"Fathers have a proprietary sense of ownership of their family, and if they feel they've failed, due to severe depression or unemployment, they may feel they don't want to subject the whole family to that humiliation," Resnick said.

"A mother won't want her children to grow up in 'this cruel world' without her, but she may feel like the father will be all right alone. That's not criminal thinking, it's distorted thinking due to depression or mental illness."

The unfathomable act isn't exclusive to one particular economic, educational or societal background, experts agree, and a criminal past is not typical.

"I think it's important to emphasize depression is often found in these cases," said Grant Duwe, a criminologist with the Minnesota Department of Corrections. "We're talking about depression that is often untreated, especially in males. For a lot of people, it's a very serious disorder that warps one's thought process."

Researchers such as Duwe have difficulty compiling familicide statistics due to the different ways the crime is classified, be it homicide or suicide, but they agree high-profile cases such as the Nov. 25 murders-suicide in Addison give the public the false impression they are on the rise.

Duwe, who wrote the 2007 book "Mass Murder in the United States - A History," said that even though the crime occurs infrequently, it remains the most common form of mass murder in the United States.

Between 1900 and 2000, there were 909 cases of mass murder - the taking of at least three lives within a 24-hour span, he said. Almost half were committed by an immediate family member, and the crime was most prevalent during the Great Depression.

"It was viewed with altruistic motives," Duwe said. "That is the one theme in familicides that has continued throughout the ages. He thinks he's doing them a favor. He's preventing them from a life of suffering. Meeting them in heaven is a frequent fantasy of the offender."