SPOKANE, Wash. -

A search warrant filed in Spokane District Court identifies the man who shot and killed an alleged car thief Monday as 56-year-old Gail Herbert Gerlach.

The warrant was used to search Gerlach's stolen Chevy Suburban March 25. The items seized by detectives include the headrest that the bullet fired from Gerlach's gun went through before striking 25-year-old Brendon Kaluza-Graham in the head. While detectives found several tools that are commonly used by car thieves, no weapons were recovered from the SUV.

The search warrant, signed by Detective Neal Gallion, shows that he is investigating the crime of 2nd Degree Murder, though Gerlach has not actually been charged with a crime at this point.

"We are investigating this as an intentional act so that's why the affidavit for the search warrant was for the crime of second murder. That would be most appropriate. Again we have not charged anyone at this time, we have not made an arrest but that is the crime we are investigating," Spokane Police Lieutenant Mark Griffiths said.

At a 1 p.m. press briefing Wednesday, police confirmed no charges or arrests have been made in the case, but the investigation is nearly complete. They added this is a "complicated investigation" and they are not ready to say whether they feel shooting was justified. While the prosecutor ultimately will decide whether or not to charge Gerlach for shooting Kaluza-Graham, the police department can make a charging recommendation based on their findings in their investigation.

In addition to seizing evidence from the Suburban after it was processed by police, authorities also seized Gerlach's 9mm and .38 handguns as evidence. He has no criminal record, has a concealed weapons permit and was carrying a gun Monday morning.

"It's our understanding that the vehicle owner had the firearm on his person at the time of the car theft," Griffiths said.

Monday morning Gerlach called 9-1-1 and told dispatchers that someone had just stolen his car and that he had shot at the suspect. That suspect, Brendon Kaluza-Graham, lost consciousness after he was hit by the single slug and crashed into a garage two blocks south on Lee Street.

Gerlach later told investigators that as Kaluza-Graham was pulling away from his home, he observed that Kaluza-Graham raised his arm, saw what he thought was a gun, thought he was going to shoot him, so he took his gun and shot one time at his Chevy Suburban. Kaluza-Graham was found slumped over inside the vehicle at 2202 E. Sharp, two blocks from where the the SUV was stolen.

The Suburban had crashed into the side of a garage and Kaluza-Graham was found with a bullet wound to the back of the skull and no exit wound. The medical examiner later confirmed he died from a single gunshot wound to the head.

While no weapons were found inside the SUV, Detective Gallion reported that they did find a flat bladed screwdriver, a flashlight, a set of keys including a shaved key in Kaluza-Graham's pocket and two more sets of shaved keys for different vehicle makes, which Gallion said are commonly used to steal vehicles.

"No gun was recovered from the vehicle," Griffiths said. "There were some keys, a couple of key rings, shaved keys which are keys that can be used to start a vehicle."

Detectives who were at the scene are wondering why Gerlach didn't shoot when he saw the thief raise his arm but rather waited until Kaluza-Graham was driving away. The fatal shot punched out the driver's side rear window and passed through the SUV's headrest before striking the driver in the back of the skull. They are indicators that any threat Kaluza-Graham had made towards Gerlach were over by the time Gerlach pulled the trigger.

"This is a more complicated investigation than some, as far as use of force, whether it was justified, so at this point we are still compiling the rest of the investigation and will confer with the prosecutor and move from there as to whether or not submit charges," Griffiths said.

Legal experts say if detectives do not believe Gerlach's use of force was justified, he could be charged with second degree murder or first degree manslaughter for Kaluza-Graham's death.