The 19-year-old man police say killed two people and himself at Columbia Mall in Howard County last weekend legally purchased a shotgun last month.
A salesman at United Gun Shop, says Darion Aguilar purchased a single-barrel shotgun from the store Dec. 10, along with a box of bucketshot (large and lethal) and birdshot (small and round) ammunition.
The shotgun can be broken down into several pieces that are less than 18 inches long, making it easy to transport.
A salesman from the store told News4's Pat Collins Aguilar was nice and polite at time of purchase, and had brought another man with him to the store that day.
Aguilar reportedly purchased the gun for home defense. It cost $430 and he paid in cash. The gun he used had a plastic grip attached, not sold at the Rockville store.
Police are still investigating the shooting and say Aguilar's motive has not been determined. Tyler Johnson, 25, and Brianna Benlolo, 21, were killed in the shooting.