A 57-year-old Reno man could spend the rest of his life behind bars for shooting and killing his elderly mother with an assault rifle in 2015.

Last week, Edward Pundyk was sentenced to life in prison with the possibility of parole after serving a minimum of 29 years, according to the Washoe County District Attorney’s Office.

He was convicted of first degree murder for the death of his mother, Delphina Medeiros, in August. Initially, he pleaded not guilty by reason of insanity, which led to a lengthy case, officials said in a news release.

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On Oct. 7, 2015, officers with the Reno Police Department responded to a report of shots fired at Pundyk’s home in Stead. When they arrived, they were told by neighbors that Pundyk was seen armed with an AK-47 assault rifle-style weapon.

Witnesses also described Pundyk as acting erratic throughout the day.

Pundyk then fired a 12-gauge shotgun in the direction of the officers as they were surrounding his house, officials said. The gunfire struck a neighbor’s house.

As SWAT team members approached the house, they found Pundyk’s mother in the front yard.

Pundyk eventually surrendered and was taken into custody.

Detectives with the police department’s Robbery Homicide Unit later learned that Pundyk shot at his mother five times with an AK-47 assault rifle and struck her at least once. The shooting stemmed from an argument between the two individuals, officials said.

Detectives also found the remains of at least four cats that appeared to have been shot to death. At least one of the cats was shot with an AR-15 rifle.

More than 50 cats were living in his home, officials said.

Deputy District Attorney Amos Stege argued that Pundyk’s actions and the nature and extent of Medeiros’ injuries warranted a higher sentence.