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David Trent Satterfield Jr. had been a suspect in the 2007 insulin overdose death of a patient at a Louisville nursing home for almost seven years, but police had little to go on to pursue an arrest.

Then on Monday, Satterfield himself called detectives to say it was true. Satterfield told investigators he was terminally ill and should spend his final days locked in a cell for injecting 86-year-old Marcelline Katherine Sommer Vale with a lethal amount of a drug she didn't need, Sgt. Donny Burbrink said Wednesday.

"He sat in our office and said, 'I want to be a resident of the Kentucky Department of Corrections,'" Burbrink said. "He said, 'I killed this woman and I want to admit it to you'. He said he injected her with a pretty good amount of insulin."

Through a jail spokeswoman, Satterfield, who has little criminal history beyond traffic violations from when he lived in the Florida panhandle, declined an interview request from The Associated Press. A preliminary hearing is scheduled for Feb. 7. A judge entered a not guilty plea on his behalf during an initial appearance on Tuesday. He is being held in the Jefferson County jail on $50,000 cash bond.

Burbrink says detectives are now combing through Satterfield's past in Kentucky, Tennessee and Florida to see if there are any other similar cases.

"We kind of got blindsided by this," he said. "We have a lot of ground work to do to close out something like this."

Joe Okruhlica, administrator of the Parkway Medical Center nursing home where police say Satterfield admitted to injecting Vale, declined to comment. Satterfield's mother and step-father are deceased. Attempts to reach multiple members of his family were unsuccessful Wednesday. Vale's granddaughter, Amanda Doyle, said the family is relieved an arrest has been made.

"We all thought it was him, but we never had any absolute proof," Doyle said.

Satterfield worked at several Louisville nursing homes through a temporary-employment agency called Select Nursing Services, which contracted with Parkway Extended Care Center to provide medical technicians, and hired him in 2005. He worked about 20 shifts at Parkway during a two-year period.

The nursing home called on Satterfield to work the overnight shift for the July 4 holiday after becoming short-staffed. Staffers on the morning shift found Vale and two other women with critically low blood-sugar readings, according to an investigation by the Kentucky Cabinet for Health and Family Services.

A nurse told investigators that Satterfield, a certified medical technician with the authority to administer medications, walked into Vale's room that morning, kissed Vale on the forehead and told her he loved her. The nurse told investigators she found it "strange behavior," but turned back to helping her patient.

Vale, who had Alzheimer's, and the two other patients, were found drenched in sweat, unresponsive and stiff. While they should have had blood glucose levels between 75 and 125, all were below a count of 25, investigators from the health and family services department concluded.

Vale died the following month. A second, 82-year-old woman also passed away. A third woman recovered. Burbrink said the second death is under investigation.

Doyle said her grandmother remained active until the end of her life, doing push-ups on her bed to show doctors how strong she was.

"She wasn't some forgotten elderly patient," Doyle said. "Everyone loved her. Because she was hilarious. And adorable."

Vale's family sued Parkway and settled for an undisclosed amount.

Satterfield, who had $37,000 in debt when he filed for bankruptcy in 2005, asked for an attorney in September 2007 after being called on to take a polygraph test and found out he was being quizzed in a homicide investigation.

When questioned by an investigator for the Kentucky Attorney General's Office, Satterfield denied ever being in Vale's room — an assertion he would make again as he cried over the implication that he would have hurt his patients.

"That would not be in the best interests of anyone personally or professionally, as well as morally. It would show that they were an amoral person," Satterfield said during an April 13, 2009 deposition, referring to anyone who would intentionally administer an overdose. "It shouldn't be in the practice of anybody that is of sound mind and soul. It's pretty despicable."

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