Ex-husband of slain Montana woman arrested in Arizona

HELENA, Mont. - Montana and Arizona authorities on Wednesday arrested a man suspected in the death of his ex-wife, whose body was found in the Yellowstone River in 2008.

Walter Larson was apprehended as he was leaving his Phoenix home for work, said John Doran, a spokesman for the Montana attorney general's office. He was being held on $500,000 bail pending extradition to Montana on charges of deliberate homicide and tampering with evidence.

Susan Casey, a 34-year-old mother of four who lived in the eastern Montana town of Glendive, was reported missing by her family on April 12, 2008. Her disappearance prompted a search of nearly 1,700 square miles that involved dozens of volunteers on horseback, foot and all-terrain vehicles.

Her body was found the next month near the town of Fallon, about 30 miles upstream from Glendive. Police until now never said how Casey died, but only characterized her death as suspicious.

On Wednesday, Phoenix police said in a statement that authorities believe Larson strangled his ex-wife and then threw her body in the river.

Larson, now 40, was arrested two days after Casey's disappearance for violating a restraining order she had filed against him in 1998. Court records said a search of his cellphone showed he made 44 calls to Casey between April 10 and April 12, 2008, the day she disappeared.

A judge dismissed the charge because Larson hadn't been notified of the restraining order.

It wasn't immediately clear what evidence had been uncovered to lead authorities to re-arrest Larson nearly four years after Casey's death. Larson had been living in Phoenix and was working in nearby Scottsdale, Phoenix police said.

It was not clear when he moved to Arizona, Doran said.

There was no immediate word on when Larson would appear in court or whether he will fight extradition, Doran said.