A gunman killed 3 people at an Indiana mall before he was shot dead by an armed bystander

A shooting rampage that killed three people and injured two others at an Indiana mall ended after an armed witness shot and killed the assailant, police said.

Around 6 p.m. local time Sunday, multiple people called 911 to report an active shooter at the Greenwood Park Mall, Greenwood Police Chief Jim Ison told reporters.

Investigators believe the unidentified gunman, an adult man, was shot and killed by a lawfully armed 22-year-old man who "observed the shooting in progress," Ison said.

Those injured or killed include one male and four females, including a 12-year-old girl whose parents brought her to a hospital with minor injuries after the shooting, the chief said.

The second injured victim was hospitalized and in stable condition as of Sunday evening, Ison said.