Speaking at the White House on Monday, Attorney General Loretta Lynch asked for "thoughts and prayers" for the family of a Massachusetts police officer shot and killed during a routine traffic stop one day earlier.

"As many of us know, we did lose another police officer just last evening in the state of Massachusetts. A Massachusetts police officer was killed on a routine traffic stop - Officer Ron Tarentino Jr. And I know some of you are aware of this but I ask that you all keep Officer Tarentino and his family in your thoughts and prayers because they're on that difficult road now," Lynch said during remarks on the state of policing around the country.

Police said 35-year-old Jorge Zambrano killed the officer during an early morning traffic stop Sunday. Police killed him later in the day during a shootout that wounded a state trooper.

Referring to the trooper, Lynch added, "I ask that you keep him in your thoughts and prayers also." The name of the 18-year veteran and former U.S. Navy Seal wasn't released.

Zambrano burst out of a bedroom closet and opened fire on officers Sunday evening as they approached him inside a duplex apartment in Oxford, investigators said. Oxford is about 7 miles south of Auburn, where the police officer was shot and killed.

"The suspect appeared from inside a closet and fired on the troopers, striking one of them," State Police Colonel Richard McKeon said. "The STOP (State Police Special Tactical Operations) team returned fire and struck the suspect."

Zambrano, who authorities said had a criminal history, was taken to a hospital, where he died.

The injured trooper suffered a gunshot wound to his left shoulder and underwent surgery late Sunday night. Officials said they expected him to make a full recovery.

"I'm extremely proud of the work done by every trooper and officer involved in today's investigation and tactical operation," McKeon said. "My pride is outweighed only by my sorrow for the Tarentino family and the Auburn police, and my concern over our injured trooper."

The violent end to the manhunt came nearly 18 hours after Officer Ronald Tarentino was shot dead by Zambrano during a traffic stop at about 12:30 a.m. in Auburn, authorities said.

The 42-year-old Tarentino was taken to a hospital, where he was pronounced dead. He had been with the Auburn police force for two years, and before that worked with the Leicester Police Department in his hometown. He leaves behind a wife and three children.

Officials said Zambrano fled the scene after the shooting. They later learned that he was at the Oxford duplex and spotted what they believed was his vehicle parked behind the building. It remained unclear why Zambrano may have shot Tarentino or why he went to the duplex.

After the manhunt, officials assured Massachusetts residents that they were safe.

State and local police officers lined up outside of the hospital Sunday as a police vehicle, escorted by a procession, took Tarentino's body to the state medical examiner's office in Boston, where the vehicle was met by another large contingent of officers.

Tarentino was the second police officer to die in the line of duty in Massachusetts this year. State police Trooper Thomas Clardy was killed March 16 when his cruiser was struck by another vehicle.

Outside the Auburn police station, the American flag was lowered to half-staff. The town's residents left bouquets of flowers and miniature American flags piled at the bottom of a stone monument dedicated to law enforcement officers who've been killed in the line of duty.

Fox News' Matt Dean and The Associated Press contributed to this report.