WOODBURN, Ore. - Authorities have released photos of a "person of interest" in the bomb blast that killed two police officers at a Woodburn bank Friday and critically injured a third.

Marion County Sheriff Rush Isham said the man was believed to have been in the Bend area in late November, where cell phones and other items were bought in order to make the bomb. The same person was believed to have been in Salem and Woodburn on Thursday and Friday to carry out his plan.

Isham said the man may have welding and electronics skills. He was described as in his 30s or 40s with a beard and dark hair. The sheriff's office would not say where the photos were taken, or say whether the man's identity is known.

"This man could be anywhere at this time," Isham said.

Woodburn police Capt. Tom Tennant and Oregon State Police Senior Trooper William Hakim were killed in the blast at the West Coast Bank.

Woodburn Police Chief Scott Russell was critically injured, but authorities said Sunday he was in stable condition at Oregon Health and Science University.

Anyone with information on the person of interest was asked to call 1-888-780-5678. There is a $35,000 reward for information leading to the arrest and conviction of the person responsible for the crime.