No indication has surfaced that George Sodini had documented mental problems, but his massacre shares threads with others analyzed by psychiatrists and legal experts, who say the line between lonely and homicidal remains hard to place.
"They're thinking, 'I want everyone to understand and appreciate why I'm doing this,' and the way to do that, in their mind, is to kill other people and not just themselves," New York attorney Carolyn Wolf, whose firm specializes in mental health issues, told The Associated Press in a telephone interview Thursday. "In their mind it sends a broader message."
The 48-year-old Sodini fatally shot himself after killing three women and wounding nine others attending a weekly Latin dance aerobics class in Collier Township on Tuesday night. He wore black workout gear and fumbled around in a duffel bag before producing three guns, firing indiscriminately after shutting off the lights.
Killed were Heidi Overmier, 46, of Carnegie, a sales manager at an amusement park; Jody Billingsley, 37, of Mount Lebanon, who worked for a medical-supply company; and Elizabeth Gannon, 49, of Pittsburgh, an X-ray technician at Allegheny General Hospital. About 75 people attended a vigil to remember them Thursday night in downtown Pittsburgh.
Police say Sodini didn't know his victims. His scathing, 4,000-plus-word blog reads like a monthslong diary lamenting his wrongful rejection by "30 million" American women and alluding to his plans.
When Virginia Tech gunman Seung-Hui Cho killed 32 people at Virginia Tech in 2007, then committed suicide, his "message" was a video tirade to NBC railing about being overlooked by "snobs" and rich "brats."
When Jiverly Wong killed 13 people and himself at a Binghamton, N.Y., immigration center in April, it was uncovered that unemployment, perceived police persecution, mockery for poor English skills and a dose of psychosis led him to kill.
It turns out Sodini bought accessories for a handgun from TGSCOM Inc. of Green Bay, Wis., the same online gun dealer that sold Cho a .22-caliber handgun two months before the Virginia Tech massacre. Police say Sodini legally owned three guns he used in the shooting.
Still, the grievances, lifestyles and mental states of the gunmen varied widely - Cho and Wong had documented mental problems, while, so far, there's no indication Sodini did.
"These people get into a very self-centered, sometimes self-aggrandizing, often psychotic path that enables them, in their mind, to finally get the attention they crave," Wolf said.
Many mass murderers feel rejected by a "pseudo community" that may exist only in their minds, said Dr. James Knoll, a forensic psychiatrist at the State University of New York's Upstate Medical University in Syracuse. He spoke Thursday at a conference he organized to analyze the actions of Wong and Cho.
"He probably worked out at this gym, he was tanning and working out, trying to improve himself," Knoll said of Sodini. "These are things he thought would get him a relationship. It wasn't working."
In his Web diary, Sodini wrote that his anger stemmed from unfulfilled desire: The women at his gym "look so beautiful as to not be human," he wrote.
Two undated videos apparently recorded by Sodini were posted online showing him touring his home and talking about hiding his emotions and trying to "emotionally connect" with people.
He notes that a sofa and chair in his living room match and says, "women will really be impressed." He also focuses on reading material on a table that includes a book titled "Date Young Women."
It's unclear when Sodini posted his screeds and videos and whether they were meant as warnings. Dr. Alan Manevitz, a psychiatrist at New York Presbyterian/Weill Cornell hospital, said the timing of such messages means everything.
"Someone who puts it out in advance may have ambivalence; they may want to be stopped," Manevitz said. "The guy who does it after the fact is leaving the explanation, the diary of what it is that they're hoping will be understood in their very irrational mind."
Ben Dobbin reported from Syracuse, N.Y.
Students and community members in San Diego County plan to march for gun control this weekend as part of a nationwide "March for Our Lives."
A stabbing outside a Costco store in Carlsbad Friday left one person seriously injured and an acquaintance of the victim's in custody on suspicion of attempted murder.
Congress gave President Donald Trump the $1.6 billion he wanted this year for his proposed "big, beautiful" border wall with Mexico but the headline number masks what he didn't get on one of his signature campaign promises.
Annual data from San Diego county medical services show an alarming number of local underage drinking deaths.
A man accused of killing his girlfriend -- a mother of two -- in the apartment they shared in the Mountain View neighborhood of San Diego must stand trial on murder and misdemeanor child endangerment charges, a judge ruled Friday.
The San Diego County unemployment rate dropped by a tenth of a percent to 3.5 percent in February amid "better-than-average" growth, according to data released Friday by the state Employment Development Department.
School shootings, for good reason, make news. Most make national news. Some even make international news.
Sheriff's detectives were conducting a follow-up investigation Friday after determining that a pair of bomb threats made against two North County high schools late Thursday night was likely part of a "swatting" hoax, authorities said.
After weeks of school threats countywide, local leaders are announcing a plan of action to put a stop to it.