Neven Glen Butler
Neven Glen Butler has been charged with the murder of an 86-year-old woman after a double sex attack Sacramento County Sheriff's Department

An 18-year-old man has been arrested in California in connection with an attack that left an elderly woman dead.

Neven Glen Butler, a North Highlands resident, allegedly attacked an 86-year-old woman and a 61-year-old woman as they exercised on a school track early in the morning.

According to investigators, the two friends were walking some distance apart when Butler jumped out from a hiding place and attacked the 61-year-old woman.

Fusako Petrus, 86, who had been walking ahead, turned and went to help her friend. Butler then sexually assaulted both of them and attacked Petrus. The injuries led to her death, said police.

Sacramento Sheriff's Department spokesman Sgt Tony Turnbull told CBS local: "She [the 61-year-old victim] started screaming, and the 86-year-old woman came to her aid. When she got there, the suspect turned his attention to [her] and attacked her.

"He sexually assaulted her and caused injuries that led to her death."

Officials said the motive for the attack was sexual assault. "Absolutely, that is the motive. That is how it all started," Turnbull said.

Butler jumped over the perimeter fence and fled the scene, but was later arrested after he attacked a 92-year-old woman on a street in Sacramento.

She was taken to the hospital for treatment.