ST. JOHN'S, Antigua  —  Beltway Sniper suspect John Muhammad planned to use explosives to rob a bank while he lived on the Caribbean island of Antigua between 2000 and 2001, according to the prime minister.

Muhammad and John Lee Malvo were arrested last month and charged with murder in a string of sniper attacks that terrorized the Washington, D.C. area. They have since been accused of attacks in two other states.

On Wednesday, Antigua Prime Minister Lester Bird told state-run radio that Muhammad is suspected of planning a crime there.

"This is a serious guy," Bird said. "There is information that he intended to rob a bank. He was seeking the explosives to do that."

Investigators have said a witness told them Muhammad once suggested kidnapping Bird for ransom. They have not identified the witness but say there is no indication Muhammad acted on the alleged threat.

The four-member task force has also determined that Muhammad, who arrived in Antigua in 2000, illegally acquired an Antiguan passport and that officials were negligent in approving the application.

The 41-year-old American was living in Antigua with his three children when he met Malvo there in 2001, officials said. Malvo, 17, is Jamaican.

The two face multiple charges in the string of shootings that left 12 dead in Alabama, Louisiana, Maryland, Virginia and Washington, D.C.