BUFFALO — Lawyers for a man charged with beheading his wife were given permission Friday to have psychiatric experts testify that he suffered from battered spouse syndrome, leading prosecutors to seek a delay in the start of his murder trial to allow them more time to prepare.

“He did suffer from persistent and constant years of abuse from his wife,” said Muzzammil “Mo” Hassan’s attorney, Julie Atti Rogers.

She said the defense would seek an acquittal by showing the February 2009 killing of Aasiya Hassan was justified.

Aasiya Hassan, 37, had threatened her estranged husband with a knife hours before her death and had also threatened to take the couple’s children with her to their native Pakistan, Rogers said.

Erie County District Attorney Frank Sedita criticized defense attorneys for waiting a year-and-a-half to make known their strategy. Hassan, 45, has changed attorneys four times since being charged.

Previous attorneys had discussed claiming Hassan experienced extreme emotional disturbance at the time of the killing, but until Friday Judge Thomas Franczyk had barred psychiatric testimony because attorneys had not filed proper notice.

“That completely changes the nature, the dynamics, the playing field of the lawsuit,” Sedita said.

Prosecutors will now have to hire their own psychiatric expert to examine Hassan, he said. Additional time will be needed to review and authenticate hundreds of newly revealed e-mails that defense lawyers said were exchanged between the Hassans.

Jury selection, which had been scheduled to begin next Wednesday in Erie County Court, was rescheduled for Jan. 10.

Muzzammil Hassan had been served with divorce papers a week before his third wife’s body was found stabbed and decapitated at the offices of Bridges TV in Orchard Park, where the couple also lived. Hassan was arrested after walking into a police station Feb. 12, 2009, and telling officers his wife was dead.

Assistant District Attorney Colleen Curtin Gable says the prosecution’s case will be built on alleged admissions, forensic evidence and “strong motive evidence.”

The couple had two young children. Muzzammil Hassan has two other children from a previous marriage.

The Hassans started the Bridges TV network in 2004, saying they wanted to counter negative stereotypes and media portrayals of Muslims and provide programming for the growing Muslim-American population.