A Town of Tonawanda man who stabbed his girlfriend to death was sentenced Thursday to 25 years in prison.

State Supreme Court Justice M. William Boller sentenced Edmund M. Serwinowski, 22, of Blackmore Street, to the maximum prison term for his first-degree manslaughter conviction.

Authorities initially charged Serwinowski with second-degree murder after the Dec. 16 stabbing of 34-year-old Jennifer Sacaridis.

Prosecutors offered Serwinowski a reduced plea to manslaughter given his psychiatric history and the wishes of the victim’s family, said Erie County District Attorney Frank A. Sedita III.

“Plus, he got the max,” Sedita said of the prison sentence.

Serwinowski in March pleaded guilty to the manslaughter charge.

The couple lived near each other and had been dating for about a month when town police were called to a Blackmore Street apartment at about 4:55 a.m. on a Sunday. Police found Serwinowski outside near the apartment.

Sacaridis was pronounced dead in Kenmore Mercy Hospital shortly thereafter.

A week before the fatal stabbing, Serwinowski had been admitted into the psychiatric unit at Erie County Medical Center, Sedita said. Police encountered Serwinowski in an incident involving another woman, who declined to press charges against him. But Serwinowski’s bizarre behavior prompted police to take him to ECMC, Sedita said.