A D.C. restaurant worker who police say fatally stabbed his girlfriend more than 40 times in December pleaded guilty to second-degree murder Wednesday.

John W. Smith Jr., 46, of Baltimore is scheduled to be sentenced March 30. He faces between 16 and 40 years in prison.

Smith pleaded guilty to the killing of Elaine Coleman, 47, whose body was found Dec. 4 in the bedroom of her Northeast Washington home. Authorities said Coleman had been dead for at least two days before her body was discovered.

In D.C. Superior Court, Smith stood before Judge Robert E. Morin and said, “I’m pleading guilty ’cause I am guilty.” In exchange for his plea, Assistant U.S. Attorney Charles Cobb agreed not to pursue any additional charges.

Coleman had been stabbed in the neck so viciously that her spinal cord was severed and she was nearly decapitated, according to court records.

Police said Smith moved into Coleman’s home, in the 500 block of 23rd Pl. NE, in July. Based on interviews with people who knew the couple, detectives described Smith as “very possessive” of Coleman. He allegedly phoned her often, keeping tabs on her whereabouts and companions, and was quick to become angry and jealous.

Coleman forced Smith out of her home on several occasions but let him return, according to court records.

Coleman wasn’t Smith’s first victim. Smith, who recently worked as a server in a Jamaican restaurant in Northeast, was charged with first-degree murder in Baltimore in 2005. Police said he stabbed a man with a pair of scissors during a fight. He pleaded guilty to manslaughter and served five years of an eight-year term, court records show.

Police and the District medical examiner originally thought that Smith also killed Coleman with a pair of scissors. But after Smith confessed to Coleman’s murder, he led them to the murder weapon, a kitchen knife, authorities said.

About 30 of Coleman’s relatives and friends took up half the courtroom during the hearing. Afterward, Coleman’s daughter, Adell Coleman, said that although she was “happy” that Smith took responsibility for her mother’s death, she hoped he would receive the maximum sentence.

“I have faith in our judicial system now that they see he has been given so many opportunities to hurt people,” said Coleman, 24. “If justice had been served before, he may not have been out on the streets to hurt my mother.”