CHICAGO (CBS) — The Chicago police officer at the center of a high-profile shooting says he had little choice but to meet “deadly force with deadly force.”

CBS 2’s Jim Williams reports Officer Robert Rialmo returned to the witness stand for the second time Wednesday.

Officer Robert Rialmo described the moments right before he fired the fatal shots.

He said he and his partner were responding to a domestic disturbance in the 4700 block of West Erie.

Bettie Jones, a neighbor, answered the door and told the officers the disturbance was “upstairs.”

Rialmo recalled hearing a rumbling, then saw Quintonio LeGrier barreling down the apartment building stairs holding a baseball bat over his head.

When asked by city lawyer Brian Gainer what he thought, Rialmo replied, “I thought he was going to take my head off.”

Rialmo said he ordered LeGrier to drop the bat several times.

Gainer asked, “Why didn’t you just run to the street?”

Rialmo replied, “It was an impossibility. He would have been on my a**.”

Rialmo said he was trained as a Chicago police officer and a Marine Corps policeman to meet deadly force with deadly force.

Attorney Brian Gainer asked, “Were you threatened by deadly force by Quintonio?”

“Yes,” Rialmo answered.

On Tuesday, Forensic Pathologist Judy Melinek testified LeGrier’s wounds were inconsistent with Rialmo’s claims that the 19-year-old had raised the bat over his head right before Rialmo fired, also killing Bettie Jones.

Rialmo testified he was injured during the incident saying, “it changed me,” but during a deposition Rialmo said he had not been hurt.

Quintonio LeGrier’s father is expected to testify tomorrow. He was at the home when his son was shot.