PROVIDENCE — Gilbert Delestre took the stand in his own defense yesterday in the Superior Court murder trial where he is accused of beating his girlfriend’s 3-year-old nephew to death.

Delestre, 27, who wore a black suit and had a fresh haircut, testified that the only time he hit Thomas “T.J.” Wright on Oct. 30, 2004, was when he hit him in the head as they were going upstairs and the boy fell backward. He maintained a composed demeanor through most of his testimony.

But prosecutor Scott Erickson questioned Delestre’s truthfulness, saying he lied about his role in the child’s death to police officers, rescue workers, his girlfriend, his girlfriend’s sister, his cousin, an investigator from the Department of Children, Youth and Families, and a prison inmate.

Prosecutors say Delestre and his girlfriend, Katherine Bunnell, became enraged when they returned to their Woonsocket apartment from a night out and found a mess in the living room. The allege that the two beat T.J. so badly that he suffered bruises, broken bones and head injuries so severe that his brain shifted in his skull. The child was declared brain dead and died the following day.

After Bunnell left the apartment to take baby sitter Kayla Roderick home, Delestre says he took T.J. upstairs. T.J. was by his side, holding a piece of his pants and the railing as they climbed the stairs.

“I told him he was a bad boy. I hit him with the back of my hand on the forehead. He fell back,” Delestre said.

He said T.J. fell back 8 or 10 steps and he tried to catch him. “I tried to reach for his arm before he went down the stairs.”

“I think he was unconscious. He can’t really speak that well. I tried to speak to him. I think I heard him say yes. I ended up putting him to bed,” Delestre said.

Dr. Deena Isaac, who was a consulting pediatrician at Hasbro Children’s Hospital at the time and attended T.J. there, testified last week that the child’s severe injuries were not consistent with a fall down the stairs.

Robert Mann, Delestre’s lawyer, said during his opening statement that Delestre never meant to kill the child and that he would ask for a manslaughter conviction rather than the first-degree murder and conspiracy he is charged with.

Delestre and Bunnell blamed each other for the boy’s death, so they were tried separately. Bunnell was convicted of second-degree murder and conspiracy and was sentenced to life with the chance of parole. Bunnell and Delestre had custody of T.J. and his two brothers in addition to their own two daughters because her sister Karen Wright was serving a prison sentence for trafficking marijuana.

When Bunnell returned from dropping off the baby sitter, Delestre said, he told her to check T.J. but he didn’t tell her what he had done because he was afraid.

Erickson railed at Delestre for his inability to tell the truth:

He didn’t tell Bunnell what he did to T.J. He didn’t tell his cousin Jose Santiago, who came back to their apartment to get his cell phone and found Bunnell holding T.J., who was limp and had stopped breathing.

“You didn’t tell rescue,” Erickson said, raising his voice. “They needed a history as to what happened to him, and you lied to them. All these people were asking you what happened to him, and you didn’t tell them.”

At the police station, he tried to make the police think the baby sitter was to blame, Erickson said, “when you knew that 15-year-old girl didn’t do anything.”

Erickson pressed Delestre on how many steps T.J. fell down the stairs, and how. “How many flips? Did his feet go over the top of his head?”

“I can’t say that, but maybe a sideways kind of flip,” Delestre said.

Erickson continued his attack on Delestre’s credibility:

•Delestre said he was not lying when he said he hit T.J. and he fell down the stairs.

•Delestre wrote a letter to Karen Wright to get pictures of his daughters, but did not admit to hitting T.J.

•He admitted lying to an investigator from DCYF because he was afraid the agency would take away his daughters.

•Erickson said Delestre told an inmate that retired Woonsocket police Sgt. Todd Brien told him to say he hit the boy and he fell down the stairs or Brien would beat him to death.

•Erickson said Delestre told the inmate that the police dragged him and put his face against the wall and were trying to break his arms behind his back.

“Was that more lies?”

“Yes,” Delestre said. He said he did not want to be known as a baby-killer in prison.

“The point is when you want something, you feel it’s OK to lie,” Erickson said.

“Yes,” Delestre said.

tpina@projo.com