The man charged in the hit-and-run death of an American University student walked away from a District halfway house Tuesday and remained free last night, officials said.

Shane Simeon DeLeon failed to return to the Community Correctional Center on New York Avenue NE by his 11 p.m. curfew, according to D.C. Department of Corrections officials. DeLeon was allowed out of the facility from 7 a.m. to 11 p.m. to remodel the basement of his girlfriend's home on MacArthur Boulevard in Northwest Washington.

Sources confirmed yesterday that a walkaway is involved in another high-profile D.C. case. They said Derrick Jackson, 19, who has been charged with first-degree murder in the death of Helen Foster-El by a stray bullet Monday night in Southeast Washington, walked away from a juvenile home in April. He had been placed there in connection with juvenile drug and stolen vehicle charges. Yesterday, police also made a second arrest in the Foster-El slaying.

Told of DeLeon's disappearance, the mother of the student killed in the hit-and-run asked, "He walked away?" An angry Kathleen O'Dell added: "He should have been in jail. This stinks."

It is the third time DeLeon has broken curfew. The first two times, he was under home detention. Renee Raymond, his court-appointed attorney, could not be reached for comment yesterday.

The absence of DeLeon, whom prosecutors had sought to have jailed pending trial, was the latest in a series of security breaches that have plagued law enforcement authorities in the area in recent weeks.

Keith Boone, 21, who has been charged with first-degree murder in the death of Dona Ferguson by a stray bullet June 16 inside her home in Capitol Heights, was on home detention at the time Ferguson was killed. According to the home detention service, Boone was abiding by his curfew when he answered two random telephone calls to his home the night Ferguson died.

A 15-year-old charged as a juvenile with assault with intent to kill while armed in a hit-and-run accident that seriously injured an 11-year-old Northwest Washington boy June 12 had also disappeared from a District juvenile facility.

As jails and prisons swell beyond capacity, courts in Washington and its suburbs are seeking creative ways to keep paroled criminals and those awaiting trial under watch but out of cells.

Escapes from halfway houses have been a constant problem for the District. Department of Human Services sources said yesterday that escapes from juvenile group homes have been increasing this year. The Washington Post reported this year that hundreds of inmates walked away from the adult facilities during a three-month period. Most of them were pretrial inmates like DeLeon. Dozens of them were rearrested on new charges, including manslaughter and armed robbery.

District officials vowed in March to improve the halfway house system, including assigning supervisors to halfway houses 24 hours a day.

Maryland legislators passed laws last year that for the first time required regulation and licensing of private home detention firms. Portions of that legislation take effect next month, but the Maryland Commission on Correctional Standards still is considering specific guidelines for the industry.

The legislative action followed a 1996 Prince George's County case in which an armed-robbery suspect who was participating in a privately run electronic monitoring program allegedly raped two women and robbed two others.

DeLeon is charged with second-degree murder in the Jan. 28 hit-and-run death of Matthew O'Dell, who was rollerblading with a friend when DeLeon allegedly struck him with his white Ford Ranger along Nebraska Avenue. The college freshman was thrown 30 feet, struck a tree and landed on his side on the concrete roadway. O'Dell was pronounced dead an hour later. Witnesses said the truck didn't brake or slow down after hitting O'Dell.

DeLeon reportedly had consumed four glasses of beer before the accident. He was arrested April 8 after an investigation that law enforcement sources said was initially slipshod. He spent a week in jail before being released and placed in the District's intensive supervision program run by the Court Services and Offender Supervision Agency. He was scheduled to plead guilty earlier this month but changed his mind.

He was not allowed to drink or drive and was required to submit to daily Breathalyzer tests and twice-a-week drug testing, according to court services spokesman Bob Murphy. DeLeon also was required to be home between 8 p.m. and 6 a.m., but was not on May 17, and was sent to a halfway house for two weeks by D.C. Superior Court Judge Patricia A. Wynn, Murphy said.

On Sunday, DeLeon again violated the home curfew, and Wynn on Monday sent him back to the halfway house, where he walked away a day later, Murphy said.

"The program has worked the way it was supposed to," Murphy said yesterday. "Something happened to him. The caseworker said he's scared to death about what's happening to his life."

Murphy said it was Wynn's decision to place DeLeon in a halfway house instead of jail. "I don't know how that decision was made," he said.

D.C. Superior Court Chief Judge Eugene N. Hamilton said yesterday that DeLeon had been "very, very closely monitored," and showed "absolutely no tendency" to walk away.

"He did not present a picture of someone who needed to be detained" in jail, Hamilton said.

However, Hamilton said, once DeLeon is found, he can be sent back to jail.

"The judge will have to look at all the circumstances," he said.

Corrections spokesman Darryl Madden said officers are "definitely out looking" for DeLeon. "This is one of those rare occasions where we did everything right."

In the Foster-El case, Jimmy J. Shelton, 18, of the 5100 block of Hanna Place SE, became the second person arrested when he turned himself in at 6th District police headquarters. Shelton was charged with first-degree murder while armed.

"There are lots of gunmen involved," said a homicide official who asked not to be named. The official said detectives still are searching for three to five other suspects. "We are getting some help [from the community], but we need some more."

Foster-El was sitting outside a neighbor's house in the crime-besieged East Capitol Dwellings in Southeast Washington early Monday night when the gunshots began. She was shot while ushering a child to safety inside the house and died before the ambulance reached her. Police said the gunfight grew out of an argument among players in an illegal craps game in the area behind the houses.

The official said detectives still are trying to piece together the events that led to the shooting.

Staff writers Sewell Chan and Sari Horwitz contributed to this report.