The man charged with the fatal hit-and-run accident of an American University student pleaded guilty yesterday to involuntary manslaughter and escape from a halfway house.

Shane DeLeon, 46, accepted a plea agreement that reduced the charge from second-degree murder. He could face up to 35 years in prison when sentenced Oct. 26.

During the 45-minute hearing before D.C. Superior Court Judge Patricia A. Wynn, DeLeon stood with his hands clasped in front of him. He stared down at the table for most of the hearing and spoke softly when answering Wynn's questions.

DeLeon is charged with running down Matthew Odell, 18, on Jan. 28, as the freshman roller-skated near the curb in the 3800 block of Nebraska Avenue NW with a friend at 7:20 p.m. Odell was thrown about 30 feet into the air, struck a tree and landed on his side on the concrete roadway. Witnesses said the white Ford Ranger truck was speeding and didn't brake or slow down after hitting Odell, who was pronounced dead about 30 minutes later at Georgetown University Hospital from blunt-force trauma.

DeLeon, a self-employed carpenter from Northwest Washington, is being held without bond in the D.C. jail.

A manager of Babe's Billiards, a Northwest Washington bar, restaurant and pool hall, has said in an interview that DeLeon had drunk at least four beers there several hours before the accident.

DeLeon initially admitted in court yesterday that he struck Odell, but said he had had only one beer. He also said he was speeding but was driving "with the flow of traffic" and had run several errands after leaving the bar but before the accident. "I wasn't impaired that night, your honor," he said.

After a brief recess with his lawyers, however, DeLeon admitted having had more than one but no more than three beers. He also acknowledged to Wynn that he had put himself and others in danger by drinking and driving.

"Nothing's ever come good of drinking and driving," DeLeon said.

DeLeon has a history of drinking and driving, which he admitted in court yesterday. He said he has gone through a rehabilitation program. He lost his Maryland driver's license in 1994 after two alcohol-related traffic convictions. He received a D.C. license even though he acknowledged on his application that his Maryland license had been revoked.

Odell's mother, Kathleen, who sat with her sister in the third row of the courtroom, fought back tears when Assistant U.S. Attorney M. Evan Corcoran recounted the details of the accident.

It occurred Jan. 28, but DeLeon was not arrested and charged until April. Wynn remanded him to a D.C.-run halfway house pending a hearing. However, DeLeon walked away in June and was rearrested two weeks later after a halfway house resident spotted DeLeon at the Greyhound bus station and reported it to police.

The high-profile case drew attention to problems within the D.C. police department's traffic investigation division. The detective initially assigned to the case failed to fully interview witnesses and collect evidence. He was removed from the unit and demoted after reports that he also bungled several other cases. Last month, he was placed on administrative leave after allegedly showing up for work drunk, police sources said.

Detective Joseph Diliberto, who was later assigned to the case and arrested DeLeon, attended yesterday's hearing.

After the hearing, Corcoran said he was satisfied with the plea agreement.

"It was important that he admitted that he killed Matthew Odell and that by drinking and driving he was putting everyone in the community at great risk," Corcoran said. "I think in excess of 30 years shows that we take this crime very seriously."

Corcoran said he is seeking "a just sentence" but declined to specify how long that would be.

DeLeon could be sentenced to 10 to 30 years in prison on the involuntary manslaughter charge and five years on the escape. Although the U.S. attorney's office agreed not to seek more than a year in prison for the escape charge, Wynn made it clear that she is not bound by that agreement.

Kathleen Odell said 35 years "would be wonderful."

"Let's hope that Judge Wynn does the appropriate thing," Odell said. "I want to see considerable jail time here. I'd like to see the maximum because we know he [DeLeon] has a previous problem with alcohol."

She said she was satisfied with DeLeon's guilty pleas. "I don't want another family member to go through what I've been through," Odell said. "He knew that . . . night he killed Matt. He knew all along."