He said it was the first time a guard has been killed at the 100-year-old facility.
Corrections officers and supporters gathered Sunday night at the entrance to the prison for a candlelight vigil in Biendl's memory. Byron Scherf, a 52-year-old inmate, was reported missing during a routine count at 9:14 p.m. Saturday. He was found three minutes later in the chapel lobby and told officers he had planned to escape.
"He is our primary suspect," Monroe police spokeswoman Debbie Willis said.
Scherf is serving a life sentence without parole after being convicted of first-degree rape and kidnapping in 1997 under the state's "three-strikes" law, Lewis said.
Prison officials said Scherf had been serving as a volunteer worker in the chapel.
Lewis said Biendl was alone at the chapel Saturday night and was not carrying a weapon, as is typical for many corrections officers.
She was ending her shift at 10 p.m. but had not reported back or turned in her equipment, which sparked concerns. Staff members immediately went to the chapel and found her unresponsive.
Emergency responders were called and Biendl was declared dead at 10:49 p.m. She was fully clothed and there was no evidence of a sexual assault, Willis said.
Biendl joined the Corrections Department in 2002. Teamsters 117 spokeswoman Tracey Thompson said Sunday that the officer had complained to her union shop steward and prison supervisors about being the sole guard working in the chapel. She worried about being there alone without anyone checking on her, Thompson said.
Recent budget cuts have forced staffing reductions and union members have been worried about the impact of those reductions on safety, Thompson said.
"We have been pushing so hard on safety issues," Thompson said. "It makes me crazy that it took someone getting murdered inside a prison while doing their job for there to be attention on this work and how difficult and dangerous it can be."
Lewis insisted that Biendl's death was not a result of budget cuts in recent years. "The staffing model has been the same for years," he said, adding that the reality is that officers often work by themselves.
Scherf entered the prison as a maximum-security offender, but through good behavior was transferred into the medium-security unit, Lewis said. Until Saturday, he had not had a violent infraction since 2001, when he tried to kill himself, Lewis said.
He was being housed in a medium-security unit at the Monroe complex, the state's largest prison with about 2,500 inmates and five units with varying security levels.
Scherf was being held in solitary confinement and the Monroe facility was in lockdown Sunday while detectives continued to investigate.
Gov. Chris Gregoire issued a statement Sunday saying she had asked Department of Corrections Secretary Eldon Vail to thoroughly review the incident and look at the safeguards in place at the Monroe complex.