The defense attorney for the Southeast Washington mother accused of killing her 6-year-old son questioned the reliability yesterday of incriminating statements the woman made to police.

Public defender Santha Sonenberg maintained that Julia Barber, 27, admitted to killing her son, Donmiguel Wilson Jr., after being harshly interrogated for hours by various detectives. By the time Barber made the statements, Sonenberg said, she was deeply troubled, exhausted and ready to say anything.

The arguments, made during a hearing yesterday, could be a preview of the defense strategy in a complicated murder case. Barber is charged with killing Donmiguel on July 18 by beating, suffocating and drowning him in the family's apartment on Wheeler Road SE; she allegedly left him, bound with duct tape, in the bathtub.

Barber has a history of mental problems, including a suicide attempt as a teenager, and a psychiatrist who examined her after the killing said she has a psychotic disorder.

D.C. Superior Court Judge Judith E. Retchin, who has ruled that Barber is competent to stand trial, did not address the question of whether prosecutors can use Barber's statements to police if the case reaches that point. She said there is enough evidence to move forward with the felony murder charge and set a follow-up hearing for Dec. 2.

New details emerged yesterday about the interrogation as well as evidence found at the scene.

Detective George Taylor, who was in charge of the crime scene, testified that Barber's fingerprints and Donmiguel's DNA were on several pieces of duct tape found in the bathtub. The pieces of tape were consistent with a roll found in the apartment, he said.

Taylor said Barber was very relaxed and comfortable when police began questioning her July 18. Although she complained of being tired, she seemed to understand the detectives' questions and initially blamed a male friend for Donmiguel's death, he said.

But about six hours into the questioning, after detectives brought Barber's mother into the room, Barber admitted that she killed her son. All told, Barber was questioned by detectives for 12 hours.

Sonenberg contended that, given Barber's mental state and the conditions under which the questioning took place, Barber's assertions were unreliable. "These statements shouldn't be given any weight," Sonenberg said.

Assistant U.S. Attorney Deborah Sines portrayed Barber as a "very intelligent, skilled defendant" who was trying to manipulate detectives.

Barber entered the courtroom yesterday wearing a blue hooded sweat shirt. When the judge asked her how she was, she responded, "A little anxious." She rocked back and forth during much of the hearing.

Julia Barber, in a 2000 photo. She is accused of drowning her son.