YORK – A South Berwick man is being held without bail at the York County Jail after the death of his girlfriend.

Jeffrey Merrifield, 41, was arrested last week after a six-hour standoff with police. He is charged with terrorizing and violating bail conditions.

His girlfriend, Kathleen Lyons, 42, died at a New Hampshire hospital Monday, a day after a domestic disturbance at the South Berwick home the couple shared.

An official cause of death has not been determined, but police say Lyons likely died of an internal head injury.

Merrifield appeared in York District Court Tuesday for a bail hearing.

Assistant District Attorney John Connelly told Judge Andre Janelle that bail should be revoked in part because of Merrifield’s criminal history.

“He certainly has demonstrated some difficulty complying with court orders in the past,” Connelly said. Merrifield paid a $500 fine for bail jumping in New Hampshire in the early 1990s.

But Clifford Strike, Merrifield’s lawyer, said the evidence against his client is based on hearsay and Merrifield never touched Lyons. He noted a police report that said Lyons was “extremely combative” with authorities.

Strike said police arrived at the house around 8 p.m., but Lyons was not transported to Wentworth-Douglass Hospital in Dover, N.H., until almost 3 a.m., according to a police report.

“It’s very unclear what happened during that time,” Strike said. “Lyons never said that Jeff Merrifield had any contact with her whatsoever.”

Connelly said a relative told police over the phone that Lyons had told them Merrifield had “punched my front tooth out.”

That relative also told police she had overheard Merrifield say he was going to get a gun and “end this,” Connelly said.

Police found no gun at the scene.

Public Safety spokesman Steve McCausland says the case is under investigation and no decision has been made whether Merrifield will be charged with a homicide.