LOCKPORT — Nicholas A. Doxey, charged in connection with the death of his 13-month-old daughter last year, brawled with his co-defendant’s father in a Niagara County Courthouse hallway after a court hearing Friday.

The fight between Doxey and Peter Nigro, father of Doxey’s girlfriend Sara E. Nigro, was quickly broken up, and after a Lockport police officer interviewed the combatants, there were no arrests.

The fight overshadowed, at least for a moment, a renewed defense attempt to have the case dismissed on the grounds that a document recently authored by the prosecution purportedly shows that no crime occurred when Sierra Marie Doxey died March 4, 2008.

At least that’s how defense attorneys E. Earl Key and Michele G. Bergevin see it. They obtained a Dec. 18 date for oral arguments about their assertion in front of County Judge Matthew J. Murphy III.

Assistant District Attorney Claudette S. Caldwell declined to comment on the contents of the bill of particulars, a document the defense demanded to supplement the indictment.

The cause of the baby’s death, at first attributed to pneumonia, was changed to a morphine overdose after toxicology test results were received three weeks later.

Doxey and Nigro, both 23 and the parents of a 6- year-old son, were indicted in June on criminally negligent homicide charges.

The prosecution asserts that the child ingested morphine in the apartment the parents then shared on Garden Street in Lockport. They now live apart.

“The parents had no knowledge of any morphine in the apartment,” Key told reporters in an interview after the fight.

He said if the case goes to trial, he intends to call an expert witness to challenge the toxicology results. Key said Sierra had been ill and also had a heart condition.

“We just can’t say 100 percent [that] morphine killed the child,” asserted Key, who represents Doxey.

Key said the prosecution’s bill of particulars accuses Doxey and Nigro of failing to provide a safe environment and properly supervise the infant.

“They’re trying to rig the indictment so they can’t lose,” Key charged. “They’re not making the allegation that [the defendants] gave the child morphine or handed it to the child or that she found it on the floor or found it in the crib.”

“There’s a difference between civil negligence and criminal negligence,” said Bergevin, Nigro’s lawyer.

A multipart hearing ended Friday on the question of whether police knew Doxey and Nigro had hired Key before they interviewed the suspects. That could make their statements inadmissible at trial. Murphy asked for written summations before ruling.

After court adjourned, Peter Nigro and Doxey tangled in a first-floor hallway.

“I came around the corner and they were rolling on the floor,” said courthouse security officer Glenn Whitlock, who broke up the fight.

“Nick pushed him,” asserted Deborah L. Hand, Sara Nigro’s mother. Hand was arrested on a harassment charge after the defendants’ arraignment June 10 for slapping her daughter’s face outside the courtroom and calling her a “baby killer.”

That case ended with an adjournment in contemplation of dismissal and a restraining order to keep Hand away from her daughter, which apparently was modified to allow Hand to attend court proceedings in the homicide case.

After Friday’s fight, Caldwell loudly urged Hand to stop coming to court.

Hand said, “They killed my 13-month-old granddaughter. They had no remorse for it.”

There is a Jan. 19 trial date, but Murphy has ordered the defendants tried separately because of Nigro’s reaction when a detective told the couple about the morphine overdose.

She told Doxey, “You were supposed to be watching her. . . . I can’t believe you did this.”

Caldwell said she wants to try Doxey first, but Key said he may have a schedule conflict with another trial. Murphy said if Key can’t get out of that, Nigro will be tried Jan. 19 despite Caldwell’s preference.