Acevedo said that the officer was working a second job as security at the hospital when the shooting happened. It all unfolded on hospital surveillance cameras.
The officer was not wearing a body camera since he wasn't on duty with HPD.
According to the chief, the man wanted to check himself into the hospital because he was in psychological distress. Around 1:20 a.m. Monday, he exited a stairwell, climbed into his truck and started cutting himself on the arm and neck before returning to the stairwell.
An unarmed security officer with Ben Taub saw a pool of blood by the truck and called for assistance.
Based on that call, the HPD officer and a DPS trooper, both in uniform, responded. Acevedo says they both identified themselves as officers and started to look for the suspect.
Acevedo said that about 15 minutes later, around 1:35 a.m., the man armed with a knife started to walk toward the officer.
The officer backed up and drew his pistol, ordering the man to stop and drop the knife, Acevedo explained.
Instead, the man ran toward the officer, who then fired at least two rounds.
Despite falling to the ground, the man got back up and ran toward the officer's personal truck and tried to take off in the vehicle, but he couldn't figure out how to put it in drive.
That's when the HPD officer and the trooper pulled him out of the vehicle and handcuffed him.
The man was wheeled inside the hospital for surgery after sustaining gunshot wounds and the self-inflicted cuts.
While the suspect tried to steal the officer's truck, Acevedo said the man bit the officer.
Acevedo was asked if the officer knew at the time that the man may have been in psychological distress.
"We don't have any information that the officers knew that he tried to check himself in, having said that, whether they know or not when an individual is coming at you and starts charging at you, starts running at you with a knife, regardless of their mental state you still have a right to defend yourself under state law and the Constitution," Acevedo said.
WATCH: Chief Art Acevedo explains officer-involved shooting and answers reporters' questions
The officer, who has been with the department for nine years, did not sustain any other injuries. He will be placed on limited duty, pending further investigation.
The trooper has been with DPS for 25 years.
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