Newport Beach police said the incident occurred around 4:13 a.m. near Indus Street and Redlands Drive. The department received a call of a man reportedly having a mental health crisis or possibly being under the influence of drugs and alcohol.
Police said as officers were responding, the man "forcibly entered" a nearby home and was shot and killed by a person inside.
Police said there is no ongoing threat to the public, and a preliminary investigation indicates it was an isolated incident.
"At this time, NBPD Detectives and Crime Scene Investigation personnel are conducting an active homicide investigation," police said in a news release.
The identity of the man killed has not been released.