An off-duty New Jersey police officer was arrested after he fatally shot his estranged wife and critically wounded her boyfriend, officials said Monday.

The deadly attack happened Sunday night at the woman's home in Jefferson Township, and Newark Police Department Lt. John Formisano, 49, was later captured in Livingston Township, Morris County prosecutors said.

Early Monday, Jefferson police told residents to look out for heavy police action.

Two children were at that home when the shooting happened, but they were not wounded.

"Due to an ongoing police crime scene investigation, very limited information can be released at this time, but there was a serious incident that occurred late Sunday night in the White Rock section of Jefferson," according to a Jefferson police statement.

"There is no danger to the public."

The woman's boyfriend is in critical condition.

Formisano is a 24-year veteran of the force, according to a Newark police spokesman.

It wasn't immediately known Monday afternoon if Formisano had hired a lawyer yet.

James Stewart Jr., president of the Newark police officer's union, said Formisano has been struggling personally because of his mother's illness and his own faltering marriage. But Formisano's arrest still came as a total shock.

"I have known John for 25 years," Stewart said. "To say that we are all shocked by the events of early this morning would be a tremendous understatement."

Stewart added that "there was no indication that any violence was being contemplated. Our hearts break for his children and our condolences go out to the shattered family of his wife. We are all just stunned."