Suspected Baton Rouge gunman Gavin Long and the three Baton Rouge officers killed in ambush.

Gavin Long, an ex-Marine who shot six police officers in Baton Rouge, Louisiana, killing three and wounding three others, reportedly suffered from post-traumatic stress disorder.

According to a new report by CNN, Long joined the Marine Corps in 2005 and worked as a data network specialist.  He was discharged at the rank of sergeant from the corp in 2010, after he serving in Iraq.

–Baton Rouge police say gunman “was seeking out” officers to “ambush”

A source told CNN’s Chris Cuomo that Long had a prescription for Ativan, an anti-anxiety drug, as well as for Valium and Lunesta.

CNN filed a Freedom of Information Act request with the military to get the records about Long’s service. Under Defense Department rules, his record are considered protected, even though he is dead. However, the records will be used during the criminal investigation.

–3 police officers killed, 3 injured during shootout in Baton Rouge

Officer Montrell Jackson and Officer Matthew Gerald, with the Baton Rouge Police Department; and Deputy Brad Garafola, with the East Baton Rouge Sheriff’s Department, were killed in the attack, while another officer, Deputy Nicholas Tullier, is still fighting for his life, according to Sheriff Sid Gautreaux.

According to authorities, Long stalked the officers before he ambushed them. He killed three and wounded three other officers before he was killed in a shootout with police.  It was his 29th birthday.

–Dallas shooting suspect identified as 25-year-old Micah Johnson

Prior to the shooting, Long posted a video to YouTube describing the Fourth of July as a day to celebrate uprisings against oppressors as he speculated on why some acts of violence were celebrated while others were considered to be criminal.

Long also sent an email to various individuals before the shooting spree, including black scholar Dr. Boyce Watkins.

“I Just want to make this crystal clear,” Long wrote.  “I have no affiliations to no one, I think my own thoughts and make my own decisions. I am influenced & directed internally NOT externally.”