MARTINEZ -- A 21-year-old Russian immigrant suspected of beating an elderly Antioch man to death was arrested Tuesday in Vancouver, Wash., just north of Portland, Ore., authorities say.

The Contra Costa District Attorney's Office on Wednesday charged Ruslan Bazelyan with murder using a deadly weapon, robbery and elder abuse in the June 10 killing of 71-year-old Ronald Henry Rush.

Deputy district attorney Mary Knox said authorities are still working to develop a motive as to why Bazelyan bludgeoned Rush in the head with a heavy crystal vase on June 10. Rush's body was found in his home in the 4400 block of Horseshoe Circle the following day.

Rush met Bazelyan in early June and offered Bazelyan a job doing gardening at his house, Knox said. Antioch police said Bazelyan was living at Rush's house and that Bazelyan fled the area in the victim's gold BMW convertible with personalized plates.

Police said Bazelyan was apprehended without out incident Tuesday in Vancouver, across the Columbia River from Portland, with help from the U.S. Marshal's Office. They believe Bazelyan was headed toward Canada when he was arrested.

Knox said it isn't known when Bazelyan will be booked into County Jail in Martinez.

Contact Malaika Fraley at 925-234-1684. Follow her at Twitter.com/malaikafraley.