ST. LOUIS -- A police detective killed a robbery suspect Friday after the man ran from investigators and pointed what turned out to be a replica pistol at them, police said.

The 40-year-old man was shot in the chest and died at a hospital shortly after the shooting.

Authorities did not immediately release the names of those involved.

Two detectives went to a residence to question a suspect in two robberies, St. Louis police Capt. James Gieseke said. A man walked up, saw the police and ran, authorities said.

A detective chased the man and caught up with him in a driveway by a garage, where the man said he wouldn't return to prison and began counting, police said. A detective fired, striking him twice.

Police said initial information suggests the shooting was justified.