"He would do whatever was needed. He's always been that way," said his son, Tom Mitchell. "If he didn't have it, he would tell you. If he did, he would help you with what he could."
Mitchell's family now fears his generosity may have contributed to his death.
Authorities allege that the boyfriend of a woman whom Mitchell had taken in killed the 74-year-old farmer, then with the girlfriend's help dumped his remains across two counties earlier this month. Tom Mitchell said investigators told him at least some of his father's remains had been burned.
Prosecutors and court documents aren't shedding light on a possible motive or what specifically led to the couple's arrest in Indianapolis, where they have connections. But Mitchell's son said items missing from his father's home, including a coin collection, leave him suspecting that Oakley Mitchell noticed the thefts and died during a confrontation.
Vishawn Mills, 24, is charged with concealing a homicidal death, while her boyfriend, 23-year-old Rayshawn Johnson faces a first-degree murder count. Both remain jailed, and their attorneys and relatives didn't return telephone messages seeking comment.
"You read about and see these types of cases in larger urban areas, and you see them on television," said Beth Kimmerling, the coroner in Illinois' largely rural McLean County, where many of Mitchell's remains turned up in the Mackinaw River. "You certainly don't expect this in central Illinois."
"I'm kind of in a daze about it," added his son, who lives in Roanoke, Ill. "It's pretty horrible."
A Navy veteran and divorced father of three children, Oakley Mitchell worked for decades at Caterpillar, taking on a union representative's post his son calls consistent with the man's desire to help others. An incurable autoimmune disease eventually forced the elder Mitchell into early retirement.
The disease worsened over time, and he suffered several other health ailments in the past year: triple-bypass heart surgery, adult-onset diabetes, a heart attack and surgery to remove a patch of skin cancer. Mitchell's deteriorating mobility had left him reliant on a motorized scooter, his son said.
Mitchell's ill health crimped his ability to get outside his two-story farmhouse a few miles from Secor, a 370-resident town with little more than a tavern and grain elevator. Alan Logue, a 57-year-old fellow Caterpillar retiree, occasionally passed Mitchell's property a mile from his and remembers it often overgrown and "never kept up very good."
Mitchell did have one scrape with the law, a 2011 arrest with son Charles Mitchell after marijuana plants were found growing on the elder Mitchell's acreage. The father was convicted of unlawfully possessing marijuana and got three months in jail, while the son, who was living with him at the time, got three years in prison.
Tom Mitchell believes his father wrongly got ensnared in that case, noting that the accused son largely was the one taking care of the property because of Mitchell's lacking mobility.
"I could tell (the charges) bothered him," Tom Mitchell said of his dad. "He'd never been locked up before that. He was a straight-up citizen."
But not one without financial issues. Oakley Mitchell went through bankruptcy in 2009, declaring $111,973 in assets but $225,412 in liabilities while drawing $1,355 a month in income. At the time, he had $173 in his checking account and $30 in savings.
Yet, Tom Mitchell said, his father took in the poor because "it kept him from being alone." Strangers were given work on the farm, and he got them clothes and rides to job interviews. He bought cigarettes for live-in guests, figuring "if you're addicted (to nicotine), you're addicted," the son said.
Tom Mitchell believes the same kindness was extended to Mills, who was licensed in Indiana as a nurse's aide.
But on Aug. 2, prosecutors allege, Johnson fatally shot Mitchell, and with Mills' help began ditching pieces of his body. Tom Mitchell knows his father was alive until at least 10:30 p.m. the previous night, when the elderly man's Facebook posting showed he had reached a new level on the Candy Crush Saga game.
The next day, fishermen found a torso in the Mackinaw River near a bridge not far from Mitchell's home. Kimmerling, the coroner, said the chest showed scars from heart-bypass surgery.
More remains turned up on Mitchell's land three days later, then even more in the Mackinaw days after that.