A bad temper allegedly led Troy Thomas to suffocate his autistic toddler son last weekend, but it was not the first time he unleashed a torrent of rage on an innocent person, according to court records.

In 2002, Thomas sexually assaulted and impregnated a 15-year-old girl who was the daughter of a friend's girlfriend. That same year, he attacked a paramedic who tried to help him, court records said.

Thomas, 25, of Aberdeen Street near Jefferson, Wynnefield, was arrested in January 2003 for the sexual attack and originally charged with rape, unlawful restraint, indecent assault and related offenses, according to records.

The girl told authorities he forcibly sexually assaulted her on her living-room floor. But Thomas told police he had consensual sex with the girl seven to 10 times that month; he denied he raped her, according to court records.

He pleaded guilty to statutory sexual assault, and prosecution was withdrawn on the other charges. He was sentenced to up to 23 months in prison and four years' probation.

After his murder arrest this week, his son's maternal grandmother maligned Thomas as a lay-about father more interested in playing video games than spending quality time with his own child. Court records indicate he was an unemployed high-school dropout, "[financially] supported by family."

Just four months before the '02 sexual assault, Thomas was arrested at Misericordia Hospital (Mercy Hospital of Philadelphia) for attacking a Philadelphia Fire Department paramedic who was trying to help him, court records show.

City medics were called to Thomas' house April 16, 2002, when Thomas' relatives couldn't rouse him from unconsciousness. The medics took him to Misercordia, where he woke up and demanded to be freed.

While restrained, Thomas threatened to "f- - - up" one medic who had delivered him to the hospital, according to records. When freed, Thomas lunged at the medic and punched him in the shoulder before being restrained again and arrested. Prosecution was withdrawn on that case, but court records don't indicate why.

Thomas' arrest record also includes several pinches for car theft and robbery, but those cases were all dismissed.

Thomas hid his checkered past from Tuesday Nelson, 24, the mother of his cherub-faced autistic son, Shaemar Nelson-Thomas. Shaemar, who was just a few weeks away from his second birthday, had recently learned to crawl and stand up straight, thanks to weekly rounds of physical therapy.

Thomas had little interest in his son, family members said, but was never violent towards the little boy.

"He told me he was a good guy," Nelson said last night. She said she found out about his extensive arrest record Thursday night when she visited Thomas at Police Headquarters.

"I felt bad. I felt deceived," Nelson said. "I asked him before if he had a history, and all I know is that he said he was a good guy."

Nelson and her family bought Thomas' act. "He was very quiet, very polite," said Mary Shaw, 73, Nelson's grandmother. "He would do just about anything you asked him to."

Police say at some point last Saturday evening, Thomas suffocated Shaemar in the basement of Nelson's mother's Kingsessing rowhouse while Nelson was asleep next to the toddler on a basement mattress.

Thomas' passions - a large television and two Xbox video game systems - sat just a few feet away from the mattress, a police source said.

"I woke up, and Troy said the baby wasn't moving," Nelson said. "I tried to wake him up, but he didn't wake up. He just looked like he was sleeping."

Nelson said Thomas never offered an explanation of what happened or showed any emotion, even after he was arrested by homicide detectives. When she saw him at Police Headquarters Thursday, "He looked like he didn't have a care in the world." *