The Montana Attorney General's office said Walter Larson was picked up in Phoenix and jailed pending extradition to Montana where he faces charges in the disappearance and death of Susan Casey.
Casey's body was found in the Yellowstone River near Fallon, Mont., three weeks after she was reported missing in April 2008.
The attorney general's office said in a written statement that Larson was charged with deliberate homicide and tampering with evidence; however no details of the evidence were announced.
Larson had been considered a possible suspect early in the investigation. The Billings (Mont.) Gazette said Larson had been arrested two days after Casey vanished for allegedly violating a restraining order.
Investigators tallied 44 calls from Larson to Casey in the days before she disappeared. The charge was later dropped because Larson had not been officially served with the restraining order, the Gazette said.
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