A 24-year-old Hamilton man has been charged with aggravated assault after a woman was attacked with a claw hammer at a Missoula motel.

Investigators say the woman suffered severe head injuries and broken bones in her jaw.

Thomas Allen was jailed on $50,000 bail and was expected to appear in court on Monday.

Missoula County Sheriff's Sgt. Mike Dominick said a woman working for an escort service arrived at Allen's hotel room late Friday. He said the two were discussing the financial transaction when Allen allegedly began hitting her head with a hammer.

Dominick says the woman screamed and a nearby friend called 911. The friend told investigators the man jumped out of the second-floor window. The friend ordered him to wait for police.