RICHFIELD — A Richfield police officer shot and killed a man who investigators say was wielding a knife.

Officers were called to a home about 9 a.m. Friday on a report of an emotionally disturbed man and a potential hostage situation.

Maj. Kip Carver of the Hennepin County sheriff’s office refused to disclose details of what happened, or to answer reporters’ questions, but called the case “a very active investigation.”

Carver said the officer who was involved in the shooting was unharmed.