A Suitland man charged with firing the stray bullet that fatally wounded a Capitol Heights woman in her living room Wednesday was supposed to be under the supervision of a home detention firm, according to court records.

The suspect, Keith Arnez Boone, 21, pleaded guilty to cocaine possession Jan. 11 and was given a suspended sentence that included home detention, a common practice in which defendants and convicts are confined to their homes during certain hours and monitored by government officials or private firms.

Two days after he was sentenced, Boone was arrested on additional drug charges but was freed on $25,000 bond. He was awaiting trial next month at the time he was arrested Thursday on a charge of first-degree murder in the death of Dona Elizabeth Ferguson, 40, who was killed by a bullet that pierced the window of her home as she was hanging curtains.

"This is every judge's worst nightmare," said Prince George's County Circuit Court Judge C. Philip Nichols Jr., who sentenced Boone to home detention. "I think that the home detention program is from time to time controversial and has had some successes and in this case a major failure."

The court records do not say which firm had responsibility for monitoring Boone, and his attorney, Douglas J. Wood, of Riverdale, said he did not know. But Wood said that Boone had not violated conditions of his home detention.

Home detention has been under attack in Prince George's since 1996, when an armed robbery suspect allegedly raped three women and robbed two others while under the watch of a privately run electronic-monitoring program.

Last year, Maryland lawmakers passed legislation that requires home detention companies to be licensed, bonded and regulated. But the arrangement still has plenty of critics who argue that the system too often breaks down and lets dangerous criminals run around unchecked.

Ferguson died Wednesday shortly after she was shot in the front room of her home in the 6800 block of Walker Mill Road in Capitol Heights. Police said that Boone had tried to shoot a 19-year-old man in retaliation for a drug deal gone bad and that the bullet broke Ferguson's window and struck her in the chest.

Prince George's police said they arrested Boone, of the 2200 block of Gaylord Drive in Suitland, at a Days Inn motel in downtown Baltimore. Three other men allegedly involved in the fight also were arrested and charged with murder.

Records show that Boone, who had no previous criminal convictions, pleaded guilty Jan. 11 to a single count of possession of cocaine with intent to distribute. Nichols gave Boone a three-year suspended sentence, placed him on probation and ordered him to enroll in a home detention program within 30 days.

Two days later, Boone was arrested again after police found 128 grams of crack cocaine, worth an estimated $25,600, and two grams of marijuana in his car in Suitland, according to court records. It was unclear why the judge in that case, whose name was not in the records, freed Boone on bond when he already was on probation and home detention. Boone is scheduled to go on trial July 28.

Court records do not include the terms of his home detention, nor when he enrolled.

Wood said that even if Boone was not home at 6:20 p.m. Wednesday -- when police say Ferguson was shot -- he was not necessarily breaking the terms of his home detention.

Generally, people under home detention are allowed to go to work and to meet various appointments, but their whereabouts are supposed to be under surveillance. Some home detention companies make participants wear electronic ankle bracelets, while others use a variety of measures to track their clients.

Wood also said Boone was innocent in the death of Ferguson, a churchgoing mother of five who had told friends she was preparing to move because she was scared by the drug dealers who congregated across the street from her home.

"I think he's getting railroaded," Wood said. "The police are trying to make an example out of a tragedy. It's tragic that this mom died, but I'm not so sure they have the right guy."

Police, who have said Boone was the triggerman, also have filed first-degree murder charges against Ronald Degaulle Rice Sr., 59, of the 1600 block of Addison Road South in Capitol Heights; his son Ronald Degaulle Rice Jr., 33, of the same address; and Leroy Dump Smith, 46, of Amherst, Va.