INDIANAPOLIS -- The city says it will investigate why Kenneth C. Anderson -- who police say fatally shot an Indianapolis police officer before dying in a gun battle Wednesday morning -- was able to retrieve nine guns that police confiscated in January.

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Authorities believe Anderson, 33, of Indianapolis, may also have killed his mother before shooting at city police officers early Wednesday.

Anderson (pictured, left) shot five officers -- killing Officer Timothy "Jake" Laird -- before another officer fatally shot him near his home in the 1700 block of East Gimber Street on the city's southeast side, police said. The other four officers are expected to recover from their injuries.

The shooting began near the home of Anderson's mother -- 2704 Dietz St. -- where officers had gone on reports of shots being fired. Inside, authorities found the body of Grace Anderson, 66, who suffered two gunshot wounds. An autopsy is pending.

Police had been to Grace Anderson's home nearly eight months earlier, on Jan. 20, when -- acting on reports that he was being combative -- officers detained Kenneth Anderson for a psychiatric evaluation, which was done at St. Francis Hospital, RTV6's Derrik Thomas reported.

On that day, police went to Kenneth Anderson's home -- not far from his mother's -- and confiscated nine guns and 227 rounds of ammunition, the city told reporters Wednesday afternoon.

Anderson eventually was released, and in February he asked for his weapons to be returned. In March, the Indianapolis Police Department determined it had no legal reason to keep the guns, and by March 11, the weapons were returned to Anderson.

On March 12, an IPD officer warned his superiors that Anderson was paranoid, had an anti-police attitude and had enough firepower to give the department's SWAT team a long fight, according to the city.

Police said Anderson was armed with an assault rifle and two other guns during Wednesday's shootings. Information on whether any of those were among the weapons confiscated in January wasn't available.

City attorney Scott Chinn said he believed IPD didn't want to return the weapons.

"My understanding is -- this is something that we'll be checking on -- that the IPD legal advisor and legal assistant were trying to think of everything they could not to return those weapons," Chinn said at a news conference Wednesday afternoon.

Indianapolis Mayor Bart Peterson promised a thorough investigation of the case.

Peterson said he wanted Chinn and city Public Safety Director Robert Turner to review:

whether policies and procedures were followed when Anderson was allowed to reclaim his weapons;

whether those policies sufficiently protect officers and citizens;

and whether -- in light of the fact that an officer noted Anderson was a threat in March -- everything possible was done to protect officers and the neighborhood on Wednesday.

"If the law says to do something and common sense says not to -- as many people in this case very clearly felt that common sense suggested (to) find some way not to give this man these weapons back -- we need to figure out a way to make the law comply with common sense," Peterson said.