Aaron Thomas, right, pleads guilty to 2009 Halloween attacks in Prince William. (Tracy A. Woodward/The Washington Post)

In the series of attacks attributed to the East Coast Rapist , the Halloween 2009 assault in Prince William County was perhaps the most brazen. He stepped out of a borrowed gold Chrysler into the cold night rain, gripped a fake 9mm handgun, pulled his jacket’s hood tight over his face and forced three teenage trick-or-treaters down a steep ravine.

The attack — the last in a string of 13 since 1997 that are linked by DNA evidence — also was the closest police had come to the serial rapist. Their sirens and footsteps interrupted his rapes after one victim summoned help via hidden texts and phone calls. He disappeared into the darkness, leaving the weapon, his DNA and the victims behind.

On Friday, more than three years after the attack, that man — Aaron Thomas — appeared in Prince William County Circuit Court to take responsibility for the crimes. He entered guilty pleas to two counts of rape and three counts of abduction. Unlike his previous appearances in court, including a failed plea hearing two weeks ago, Thomas was alert, responding quickly and forcefully to Judge Mary Grace O’Brien’s questions.

“I would like to take responsibility for my problem and the pain I’ve caused,” Thomas said. “I am guilty.”

O’Brien accepted Thomas’s pleas, meaning Thomas, 41, has been convicted of three rapes, including the guilty plea he entered Thursday in Loudoun County for a 2001 attack in Leesburg. The rapes are fewer than a quarter of those both Thomas and police say he committed, but they are enough, potentially, to land him behind bars for a maximum of seven life terms.

Explore the timeline

The pleas spare those victims from having to go through what would certainly have been difficult trials. It is unclear how several other jurisdictions will proceed in cases they could prosecute. Thomas’s DNA has linked him to rapes in Fairfax and Prince George’s counties, as well as in New Haven, Conn., where Thomas lived at the time of his arrest in 2011. He also has been linked to a peeping Tom incident in Cranston, R.I., and police think that there are cases elsewhere.

“It’s good to get it over with, and I’m glad the girls didn’t have to testify again,” said Commonwealth’s Attorney Paul B. Ebert, who prosecuted Thomas with assistants James Willett and Amy Ashworth.

The three victims of the Halloween attack testified against Thomas in a preliminary hearing in March, speaking courageously about the terror they faced as a stranger repeatedly said he would kill them. They said they felt that they couldn’t flee out of fear they would die trying; one carefully texted and called for help with a phone tucked into her sleeve.

“I was scared,” one victim said. “I was praying. I thought that was it. I thought I was going to die.”

In that hearing, Thomas put his head down on the defense table, unable to look at his victims.

“I was melting in my seat,” he said later in a telephone interview with The Washington Post. “I was disgusted.”

On Friday, defense attorneys took the unusual step of asking that Thomas be allowed to sit in an observation room adjacent to the courtroom for the testimony of county police 1st Sgt. Liam Burke. O’Brien let Thomas leave; he did not return.

A letter of apology handwritten by Aaron Thomas that he wrote on March 4, 2011, after he was interrogated by police.

The Prince William attack was the first time Thomas corralled three victims at once, although he had previously attacked two women at the same time, according to police. At the time of the Halloween attack, Thomas was visiting former girlfriend Jewell Hicks in Northern Virginia, he and Hicks told The Post. Thomas grabbed a replica 9mm handgun — which was really a lighter — from Hicks’s apartment and borrowed her car. He drove to Prince William, close to where he and Hicks once owned a home.

Thomas said he saw the girls and then forced them into a wooded area. When he heard footsteps approaching, he said, he ran, tossing the lighter aside and circling back to the car, which was parked nearby. He and Hicks later returned to the scene to look for the lighter, which he — and police — never found. Soon after, Thomas returned to New Haven, where he was captured a year and a half later.

Burke said Thomas confessed to the Halloween rapes, and Ebert said after the hearing that Thomas confessed to every rape case that police had linked to him. Prosecutors entered transcripts of those interrogations into evidence, along with transcripts of Thomas’s phone calls to The Post.

Thomas will be sentenced in both Prince William and Loudoun counties, where he faces a minimum of 95 years and a maximum of seven life terms. There is no parole in Virginia; those convicted in the state must serve at least 85 percent of their sentences, which in Thomas’s case would be no fewer than 80 years.