VIDEO: Off-duty officer stops gunman at Kansas City Costco

KANSAS CITY, Kan. (KABC) -- An off-duty officer confronted an armed man who threatened to open fire inside a Kansas City Costco.

The man said he was an off-duty U.S. Marshall and was there to kill people, investigators said. That caused shoppers to run for their lives.

Capt. Michael Howell was able to sneak up on the armed suspect and ask him to drop his weapon. But the man refused and turned to Howell. That's when the officer shot and killed the gunman.

Investigators later learned the gunman was not a U.S. Marshall.

No one, including the officer, was injured in the shooting.