Warning: the above video contains graphic content. 

Vietnam veteran and convicted killer Andrew H. Brannan was put to death this week for murdering a rookie police officer in Georgia over 15 years ago.

According to The Washington Post, Brannan was given a lethal injection Tuesday evening when his PTSD defense fell short. The shooting took place in Lauren County, Georgia in 1998 when Deputy Kyle Dinkheller pulled over Brannan for driving 100 mph. Brannan steps out the car and screams about his time in the Vietnam War before teasing the cop about shooting him. Brannan then pulls an M1 Garand rifle out of his vehicle and exchanges gunfire with the officer. Despite being hit in the stomach by a round from the officer's handgun, Brannan methodically shoots the officer in his legs and arms before walking up and firing a kill shot into the officer's eye.

Dash cam footage caught the extremely hard to watch incident on camera, as well as Dinkheller's terrified screams. Since then, the case has been used in training facilities all around the country.

Brannan's lawyers tried to convince prosecutors that the 66-year-old faced severe mental instability after serving as a first lieutenant in the Army in Vietnam from June to December in 1970.

"Andrew's combat experience forever altered his personality and his life," his lawyers said. "Although he initially re-entered civilian life, he soon began to manifest signs of serious mental illness, which grew worse over time."

Brannan's final statement was dedicated to other veterans around the country.

"I am proud to have been able to walk point for my comrades, and pray that the same thing does not happen to any of them."

Source: The Washington Post | Video Credit: YouTube