Updated 6:47 p.m.

Marcine Herinck never tired of community service, even after the 89-year-old could no longer drive herself to and from the food pantry and thrift store in Northeast Portland. She simply finagled rides from her family.

That devotion may have led to her death.

A registered sex offender with a self-described history of mental illness is suspected of killing the 4-foot-10 grandmother after he trailed her home from her volunteer shift at Portland Adventist Community Services.

Authorities on Wednesday charged Timothy Joseph Mackley, 58, in Herinck's death. Her body was found in Mackley's car Monday night during a traffic stop, police said.

Timothy J. Mackley

Herink's family announced her death Tuesday night on Facebook. They had last seen her Sept. 18, when her daughter-in-law dropped her at the Wilkes neighborhood home where she lived alone.

"Marcine will be remembered for her soft, gentle spirit and the life she lived dedicated to others," the family said.

That commitment shined at the faith-based service center on Northeast Halsey Street where she began volunteering in 2014. Mark Fulop, the organization's executive director, said Herinck had logged more than 1,900 hours stocking and cleaning shelves in the thrift store.

"She brought her wit, her humor and a passion for community service," he told The Oregonian/OregonLive. "She was loved by staff and customers."

Mackley might have been one of the people she had helped. He had been in the store during Herinck's final shift, Fulop said. Staff members contacted detectives about Mackley after Herinck was missing for several days, he said.

According to police, detectives two days ago determined Mackley was involved in Herinck's disappearance. Authorities suspect Mackley saw her at the faith-based service center and followed her home.

When police stopped his Toyota Camry in the 9200 block of Southeast Holgate Boulevard, officers discovered the remains in the trunk of his car and arrested him, said Sgt. Chris Burley, a Portland police spokesman.

An autopsy by the Oregon State Medical Examiner's Office ruled the woman's death a homicide. Authorities didn't say how she was killed.

Mackley pleaded not guilty Wednesday to murder charges in Multnomah County Circuit Court.

He appeared to roll his eyes, bounce up and down and speak to himself during the arraignment. At various points Mackley turned his back to the judge and to members of the courtroom.

Some in the audience gasped. Others cried. Mackley was ordered held without bail.

"It's been very, very troubling for us," Jeff Herinck Sr., Marcine's son, said after the hearing. "She was a great person."

Records show Mackley was convicted in 1989 of sodomy and sex abuse and sentenced to 20 years in prison. He was later ordered not to be around any children or schools.

After his release, he failed to register as a sex offender and has told court officials he was diagnosed as having bipolar disorder and schizophrenia, records show.

Mackley told court officials he lives on disability payments of less than $1,000 a month and drives people to Alcoholics Anonymous meetings in his spare time.

His apartment was less than two miles from where Herinck went missing last week and about three miles from Portland Adventist Community Services, records show.

Her disappearance prompted a frantic search to find her.

Friends, family and volunteers plastered fliers around her home in the 1500 block of Northeast 150th Avenue. They used a drone to fly over woods and brushy areas, they said.

Police, meanwhile, asked the public for help and distributed photos of Herinck.

Herinck had early stage dementia and didn't drive, her family said. But she still lived alone and babysat her grandchildren. She attended church regularly, where she led Bible studies and organized toy drives for kids.

"Marcine was one of those quiet rocks in our community," said Chris Blair, the pastor at Crossroads Church on Northeast 102nd Avenue. "She was a tiny little thing. But she had boundless energy."

Jeff Herinck told KATU News that he drove to his mother's house a week ago on Sept. 19 and found it empty.

The front and garage doors were open. His mother's cellphone, purse and keys were still in the kitchen. A cup of cold coffee sat in the microwave.

"I just feel something has happened to her," Jeff Herinck told KATU. "I just feel like she was taken, I really do."

The Oregonian/OregonLive's Everton Bailey, Jr., Maxine Bernstein, Aimee Green and Jim Ryan contributed to this report

-- Shane Dixon Kavanaugh

skavanaugh@oregonian.com

503-294-7632 || @shanedkavanaugh