Investigators believe the suspect, Brigitte Harris, "did it," a law enforcement official said on Monday. "We are trying to determine why."
The official, who spoke on condition of anonymity because Harris had not been arrested or charged, said police were checking reports that Eric Goodridge, 55, may have abused Harris as a child. Detectives were hoping to question the 26-year-old suspect at a hospital mental ward where she was admitted after the slaying, the law enforcement official said.
Police also were seeking a search warrant to comb the suspect's computer files for clues about a motive. On her MySpace.com home page, she referred to herself as The Original Dark Angel and listed her mood as "depressed."
Her attorney, Arthur Aidala, after viewing the MySpace page, said, "You could tell that she's someone who's calling out for help."
He said his client's stepfather was "a monster."
"And living with a monster from the age of 3 is something that you just don't recover from without professional help," he said.
Harris left chilling notes in her Rockaways apartment accusing Goodridge of abuse and justifying her crime, the New York Daily News reports.
"He wrecked my life," read one note found near her stepfather's body Saturday, according to the Daily News. "At first, I blamed myself. Now I know it's not my fault," another said.
Police said Harris sent e-mails to Goodridge to lure him to her apartment, the Daily News reports. Then she handcuffed him to a chair, gagged him with duct tape and throttled him until he died, authorities said.
He was already dead when she cut off his penis, officials said, noting there would have been much more blood if he had been alive when it was severed.
When officers were summoned there at about 1 p.m. Saturday, they discovered his mutilated body; Harris was missing.
The victim had been bound with duct tape, handcuffed and strangled before having his penis sliced off, police said. The medical examiner determined he died from "homicidal violence," including gagging and neck compression.
Police immediately began searching for Harris and learned she had checked into a hospital for psychological treatment.
Goodridge lived in Staten Island when he was married to Harris' mother. He later married another woman, who died five years ago, according to the Daily News. That woman's mother defended Goodridge as a decent dad to his other children, who are now orphaned.
She acknowledged to the Daily News that she had heard rumors that Goodridge had abused Harris, but said she didn't think they was true.
"I would die if I could believe that," his former mother-in-law told the Daily News. "He wouldn't pay child support, but I wouldn't believe that."
But a former brother-in-law told the Daily News he had also heard of the sex abuse claims long before Goodridge's shocking death.
"It stands to reason if someone pulls a Lorena Bobbitt, there's a good reason," he told the Daily News.