Six people were on board when the plane crashed in a post office parking lot.

Five people were killed when a small plane crashed in the parking lot of a Lafayette, Louisiana, post office on Saturday, fire officials said.

The two-engine Piper Cheyenne took off from the Lafayette Regional Airport and then crashed one mile away “under unknown circumstances,” said officials with the Federal Aviation Administration (FAA).

Six people were on board at the time of the accident, which was shortly after 9:20 a.m. local time, Lafayette Police Sgt. Paul Mouton told ABC News.

The one survivor on the plane was taken to a hospital, Lafayette Fire Chief Robert Benoit told reporters.

After crashing in the parking lot, the plane struck a car, Mouton said.

Three people on the ground were hospitalized, Benoit said.

Investigators with the FAA and National Transportation Safety Board are headed to the accident site.

This is a developing story. Please check back for updates.