A former security guard accused of torturing his 7-year-old stepdaughter to death had the audacity to try to shift the blame to the child’s mother and even the tiny victim, a prosecutor said during a blistering closing argument yesterday at the man’s murder trial. An assistant district attorney, Ama Dwimoh, displayed a gruesome crime scene photo of Nixzmary Brown’s battered corpse — skeletal, topless, and splayed on a wooden floor — as she alternately scolded and mocked the defendant, Cesar Rodriguez.

“He’s nothing short of a murderer,” she told jurors, her voice rising. “Cesar Rodriguez is a murderer!”

Moments later, Ms. Dwimoh positioned herself in front of the defense table and glared at Mr. Rodriguez.

“Now he’s having you believe, ‘It ain’t me, it’s my wife.’ Hmm!” she told the jury of 10 women and two men.

Finally, gazing up at the photo, she argued: “There is nothing that 7-year-old Nixzmary Brown could ever do to deserve that.”

Earlier, the defense attorney, Jeffrey Schwartz, had sought to convince jurors that, though his client had punished an unruly Nixzmary with beatings, her “demented” mother was the killer.

Mr. Rodriguez, 29, “is guilty of child abuse,” the lawyer said. But he added: “You have not seen evidence in this courtroom that has proven murder or manslaughter charges.”

Deliberations were expected to begin today.

The defendant pleaded not guilty to charges he killed Nixzmary on January 11, 2006, with a blow to the head after catching the starving child stealing yogurt. Authorities say the victim had been routinely bound to a small chair, whipped with a belt, and forced to use a cat litter box as a toilet — allegations that shocked the city and hastened child welfare reforms.

The prosecution’s case relied heavily on a taped interview of Mr. Rodriguez saying that on Nixzmary’s last night he stuck her head under running bath water “to make her think.” Investigators suspect the girl’s head was smashed against the faucet — something her stepfather denied doing.

In the tape the father conceded, “Sometimes she’d get me real angry, and I used to just throw her on the floor. … She was always lying to me about everything.”

Mr. Schwartz asked jurors to focus instead on the testimony of a jailhouse snitch, who claimed that behind bars the girl’s mother, Nixzaliz Santiago, admitted being haunted by the death and indicated she delivered the fatal blow.

It was “the confession of the sick, of the demented, of the disturbed mother,” Mr. Schwartz said, referring to Ms. Santiago as “Mommy Dearest.”

Ms. Dwimoh countered that the stepfather and the mother, who also has pleaded not guilty and is awaiting a separate trial later this year, were at fault.

“Don’t worry about Nixzaliz Santiago,” the prosecutor said. “She’ll have her day. Today is Cesar Rodriguez’s day.”