PORTLAND, Ore. — A 15-year-old boy is facing murder charges after he shot and killed an 18-year-old at a Motel 6 last December, police say.

Police say Jeremiah Hannon shot and killed 18-year-old Ian Olson inside a room at the Motel 6 in the Lloyd Center on Dec. 22, 2018.

Olson's body was found at about 11:15 a.m. by a housekeeper of the motel, located at 518 NE Holladay St

RELATED: Teen found dead at Portland Motel 6 was shot and killed, officials say

Police also say Hannon and another teenager beat up a man aboard a MAX train just five days after the shooting. 

That victim in that case told police he had asked the teens to turn down the music they were playing on the train before they attacked him at the Lloyd Center stop.

The victim's jaw was broken in two places and he lost several teeth in the attack. 

His wife and 10-year-old daughter witnessed the attack. 

"It saddens me and angers me," said the victim, Robert Valentino. "Our job is to protect our kids and let them know they're safe. And I wasn't able to do that." 

RELATED: Portland man says teens broke his jaw after he asked them to turn down music on the MAX