ORLANDO, Fla. — An Orlando police sergeant was shot and killed Monday after approaching a suspect wanted for questioning in the murder of his pregnant ex-girlfriend.

A second law enforcement officer was killed in a motorcycle crash while responding to a massive manhunt for the suspect.

More than a dozen schools were placed in lockdown during the manhunt, and authorities were offering a $60,000 reward for information leading to the arrest of Markeith Loyd, the 41-year-old suspect wanted in the killing of Master Sergeant Debra Clayton.

Officers and deputies focused their manhunt on an apartment complex in northwest Orlando, and dozens of residences had been searched.

Clayton, 42, was killed outside a Walmart store in northwest Orlando early Monday, and Orange County Sheriff’s Office Deputy First Class Norman Lewis was killed in a crash while responding to a manhunt for Loyd.

Another Orlando police officer was involved in a crash while responding to the shooting but had only minor injuries.

Authorities said Loyd previously was a suspect in the murder of his pregnant ex-girlfriend in December.

‘‘He should be considered armed and dangerous,’’ Police Chief John Mina said at a morning press conference. Later in the day, the chief said, ‘‘It doesn’t matter where he is. We will track him down to the ends of the Earth.’’

Mina lauded Clayton, a 17-year veteran of the force as a ‘‘committed’’ officer and ‘‘a hero’’ who gave her life to the community she loves. The Orlando Police Department said in a tweet that Clayton always had a smile and a high five for every child she came across.

Associated Press