(CBS) — We are learning more about the police officer who fired those fatal shots.

The officer’s name is not being released at this time by Chicago Police or the Independent Police Review Authority, but sources tell CBS 2’s Mai Martinez he has been with the Chicago Police Department for a little more than three years.

He currently works in the 11th District and he’s assigned to the midnight shift. The officer is in his 20s and is a former Marine.

He entered the academy in October of 2012 and graduated six months later in March of 2013.

Under CPD policy at the time he would’ve been a probationary police officer for 18-months, so that means at the time of Saturday’s shooting, he had only been off probationary status and been a full-fledge officer for a little more than a year.

We’ve also run the officer’s name through a public database to see if he has any complaints against him. Currently we’ve found none.

19-year-old Quintonio LeGrier and 55-year-old Bettie Jones were killed in the shooting early Saturday morning.