FARMINGTON, N.M. (KRQE) – Investigators are getting a clearer picture of the timeline leading up to a deadly mass shooting in Farmington. Police revealed Thursday Beau Wilson purchased 220 rounds of ammunition on May 13, two days before he opened fire in a neighborhood.

That’s on top of the three 30-round magazines investigators say he obtained ahead of time. Police say Wilson shot randomly when he killed three elderly women and wounded six others, including a Farmington officer and a state police officer.

In body camera footage, Officer Andreas Stamatiadis tells dispatch he’s driving himself to the hospital. The round shattered his driver-side window, so Officer Stamatiadis used his other hand to punch it out so he could see better.

After the shooting, Farmington police found nearly 160 rounds of ammo in a backpack at Wilson’s home – 125 rounds of .223 rifle ammunition and 34 rounds of 9mm ammunition. Along with two fully-loaded 30-round magazines that were taped together, which investigators believe would make reloading easier.