Pittsburgh detectives checking whether accused child rapist Clyde E. Haidle might be a suspect in other sex crimes have combed through unsolved cases dating to 2001 and come up empty.

Mr. Haidle, 46, is accused of snatching an 11-year-old girl off a Greenfield Street Thursday afternoon and raping her in an abandoned house.

"There's no reason to believe this was anything other than an isolated incident," sex assault squad Sgt. Larry Scirotto said yesterday.

Sgt. Scirotto said the case is unusual in two ways: Pittsburgh does not have many sexual assaults of children by strangers; and while Mr. Haidle has an arrest record for minor offenses such as assault and disorderly conduct, police have not found any history of sex crimes that would be a prelude to such a horrific act as raping a child.

"It's very odd to be the first time," Sgt. Scirotto said.

Although the girl did not recognize Mr. Haidle, police said he told them he had seen her over the past few years in the neighborhood.

Police said Mr. Haidle was drinking on the porch of a vacant house at 446 Ivondale St. Thursday afternoon when he spoke for about 30 seconds with the girl, who was walking on a set of city steps that run alongside the property. She had recently gotten off a school bus in the area.

Mr. Haidle was with former girlfriend Carol Gault -- she said in an interview yesterday that she was now just his landlady -- and their roommate, Anthony Rogers.

That brief chat served to build a base level of comfort between the girl and Mr. Haidle, according to Sgt. Scirotto.

The girl left, and eventually Ms. Gault and Mr. Rogers did, too. For some reason, the girl reappeared. It was then, police said, that Mr. Haidle grabbed her by the neck and took her into the abandoned house and raped her, a police affidavit said.

After the brief assault, Mr. Haidle took the girl's underwear and cell phone and let her go.

She fled down Ivondale, where she ran into Nina and Shawn Kopa, who were playing outside with their three children.

"Some girl started running down the street. I didn't think anything of it because kids run. But she just ran up to us and said, 'Help me, please. Some guy just raped me at that abandoned house down there,' " Mrs. Kopa said.

She took the girl inside and called 911 while her husband headed off to the vacant house.

"She looked shocked, like traumatized. You could tell that something wasn't right," Mrs. Kopa, 29, said.

"I just kind of rubbed her back and told her, 'It's a shame things happen and no one should have to go through things like that.'

"Her clothes were on fine and everything. She didn't look like she was physically harmed or anything. Even her hair wasn't messed up. She looked like she'd seen a ghost."

Meanwhile, police said, Mr. Haidle headed back to his house on Naylor Street. Sgt. Scirotto said Mr. Haidle watched the news at 5 p.m., which had a segment about the crime, and mentioned to Ms. Gault that he might be in trouble.

The girl described her attacker and his clothing. A man in the neighborhood told police that the description matched Mr. Haidle.

Armed with that information, police used a bloodhound to track Mr. Haidle's scent to his house. Officers and sheriff's deputies led by Lt. Jack Kearney found Mr. Haidle hiding in a homemade trap door on the second floor.

Mr. Haidle had cut a crawl space into the floor boards and covered it with an area rug and a milk crate nailed to the floor. He was found inside on his stomach with his arms outstretched and was shocked with a Taser when he refused to come out and show his hands.

Police said they found the girl's underwear in the crawl space. Sgt. Scirotto also said police had DNA evidence linking Mr. Haidle to the assault.

Sgt. Scirotto said the motive for the assault was not known. It did not appear, though, that the girl was targeted or that Mr. Haidle was stalking her or waiting for her to get off the school bus.

Mr. Haidle admitted to having oral sex with the girl but said he thought she was 15 years old, the affidavit said.

Mr. Haidle was arraigned yesterday in City Court on charges of indecent assault, false imprisonment, rape, involuntary deviate sexual intercourse, endangering the welfare of children and corruption of minors. He is being held on $150,000 straight bond and must be seen at the jail's behavior clinic.

City officials yesterday filed legal action against the owners of the abandoned property, Andrew and Julia Supira. The owners were cited March 31 by the city's Bureau of Building Inspection for numerous violations that have not been rectified.