In confessing that he was the Center City rapist and begging for a city's forgiveness, Troy Graves portrayed himself as ready to finally tell all.

He even said he would sit down with FBI profilers to help them understand the psyche of a serial rapist and killer.

But was his confession the full truth?

The answer is unclear.

Despite his apparent lack of self-pity, Graves' narrative seems in places to be inconsistent with the statements of other witnesses and other evidence.

For one thing, Graves described his attacks as impulsive, the unpremeditated assaults of a man driven by psychic pressures beyond his control.

Yet detectives say they still believe that Graves had carefully hatched his attack plans - stalking victims, studying their residences - before striking.

"He told me he'd been watching me," said a 1997 Philadelphia victim, the first of his six in the city. "He told me I was beautiful and worth finding a way to break in for."

More important, Graves told detectives that he had choked student Shannon Schieber in her apartment near Rittenhouse Square and made good his escape without seeing any sign of police.

This statement, too, seems at odds with other evidence.

At stake here is more than a matter of chronology.

That's because Schieber's parents are pursuing a federal lawsuit against police, contending that their daughter was still alive in May 1998 when police pounded on the door. The core contention of the suit is that Graves was still in the apartment at that moment - and police, by not bursting in, missed the chance to save her life and catch him.

Graves gave his confession and description of events at a time when his lawyers were in the middle of negotiations, ultimately successful, that enabled him to plead guilty and receive two consecutive life sentences rather than the death penalty.

While Graves, in his confession, insists that he was gone by the time police arrived, witnesses and a time log of 911 calls raise doubts about whether he could have escaped unnoticed.

In his account to detectives, Graves said he was struggling with Schieber when he first heard a knock on the door.

He said he and Schieber continued battling until finally he strangled her. Just after he had choked her unconscious, Graves said, he heard a second knock, about 10 minutes after the first.

He heard someone calling Shannon's name, he said, but he never heard anyone shout "police."

The implication is that the second knock must have been a neighbor trying again to rouse Shannon before police arrived, because neighbors and the responding police officers agree that the officers loudly identified themselves.

After the second knock, Graves said, he watched the street outside for at least five minutes before fleeing. During that time, he said, he saw and heard no one in the street.

In all, Graves said, about 15 to 25 minutes passed from the time he heard the first knock until he ran away.

An apparent problem with his narrative is that other evidence seems to show that police arrived less than 15 minutes after the first knock.

According to a deposition taken as part of the Schiebers' lawsuit, one of Schieber's neighbors heard her scream, knocked in alarm on her door for the first time at about 2 a.m., and called 911 within a few minutes.

Police records show that this neighbor called police at 2:04 a.m. and that two responding officers got there at 2:11 a.m.

Moreover, depositions in the lawsuit suggest that it would have been difficult for Graves to slip away without being observed during the few minutes before the police arrived.

Graves said he escaped by climbing out a balcony from Schieber's second-story apartment, dropping to the street, and running off.

But a tenant of the building said that she had been standing at her outside door, right under that balcony, from about 2:05 a.m. until police got there - and saw nothing.

In a bitter press conference Thursday after Graves pleaded guilty to killing their daughter, the Schiebers said it appeared that he might have tailored his testimony to exonerate the police.

This suggestion outraged the homicide detectives who interviewed Graves.

"What he said we put down," said Detective Jeffrey F. Piree. "All we wanted were the facts and the truth. And that's what we got."

Graves' confession also appeared to shoot down another key ingredient of the lawsuit.

Call it the mystery of the balcony door.

In his statement to detectives, Graves said that as he fled the murder scene, he slid shut the balcony door.

This seemingly small detail assumes importance because both the Schiebers and police agree the door was open the next day when Schieber's body was found by her brother.

Witnesses and police agreed that the door was closed when police inspected the exterior of the apartment building the night before during their five-minute visit in response to the 911 call.

The lawsuit contends that the evidence that the door was closed when police arrived, but open the next morning, leads to one conclusion: The killer was inside when police got there and slipped away after they left, leaving the door open behind him.

But police say Graves' statement that he closed the door means he had already left by the time they arrived.

Why then, in their view, was the door open the next day?

In her own news conference Thursday, Philadelphia District Attorney Lynne M. Abraham suggested that Shannon's brother had himself opened it after he became sick at the sight of his sister's body.

But the brother, Sean Schieber, called that suggestion "preposterous."

He and a friend who was with him when the body was found have insisted in depositions that they saw that the door was open even before they entered Schieber's apartment.

Moreover, Martin Halek, a friend of Shannon Schieber, recalled in a deposition that Sean Schieber called him before entering his sister's apartment building - and had said right then that he was especially concerned because the door was open.

"Her balcony door was open and he yelled up there or whatever, there was no response," Halek recalled.