Gavin Long, the Marine vet who shot six law-enforcement officers Sunday in Baton Rouge, La., resulting in the death of three officers, suffered from post-traumatic stress disorder, CNN reports, according to a source involved in the investigation.
Long, 29, served in the Marine Corps 2005-2010 as a data network specialist. His tenure included a deployment to Iraq.
According to CNN, the source said that Long had filled a prescription for Ativan, a medication used to treat anxiety, as recently as June. He also reportedly had prescriptions for valium and Lunesta.
Law-enforcement officials believe that Long "stalked" the officers before ambushing some of them in a "targeted" attack.
"There is no doubt whatsoever that these officers were targeted and assassinated," Louisiana State Police Col. Michael D. Edmonson said, according to the network.
Baton Rouge Police Officers Montrell Jackson and Matthew Gerald, as well as East Baton Rouge Sheriff's Deputy Brad Garafola, were fatally shot in the attack.
Sheriff's Deputy Nicholas Tullier was critically injured and is "fighting for his life," Sheriff Sid Gautreaux said.
The other two officers suffered non-life-threatening injuries.
Read more at CNN.