Mar. 9--A former Army Ranger convicted two years ago of masterminding the takeover-style robbery of a Tacoma bank branch was sentenced Monday to an additional 20 years in prison for soliciting the murder of an assistant U.S. attorney and assaulting a fellow inmate.

Luke Elliott Sommer, 23, previously pleaded guilty to solicitation of a crime of violence and assault with a deadly weapon. Both crimes occurred last year while Sommer was serving a 24-year sentence in the robbery case.

Federal prosecutors said he offered an undercover agent $20,000 to kill the assistant U.S. attorney and make sure it appeared to be "murder, not an accident," the U.S. Attorney's Office in Seattle reported.

Prosecutors also said Sommer used a prison-made knife to attack a fellow inmate who was a co-defendant in the bank robbery case.

"There is no doubt that the defendant is a very dangerous man and needs to be locked up to protect society," said assistant U.S. attorney Gregory Gruber, who prosecuted the solicitation and assault cases.

Sommer planned and participated in the August 2006 robbery of a Tacoma Bank of America branch. He and four accomplices -- all wearing body armor -- used AK-47s and semiautomatic handguns to rob the bank.

Adam Lynn, staff writer

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