(CNN) -- Ohio authorities on Saturday advanced their investigation into killings tied to a Craigslist job listing when they identified the last of three bodies found last month, a sheriff said.
The body of Ralph H. Geiger, 56, of Akron, Ohio, was identified by the Licking County coroner's office, said Sheriff Stephen S. Hannum of Noble County. His corpse had been discovered by investigators November 25 in a shallow grave in eastern Ohio.
He and two other men found dead -- also in different shallow graves -- are believed to have been killed after answering a Craigslist ad to work on a cattle farm in eastern Ohio, authorities said.
Brogan Rafferty, 16, of Stow, Ohio, who is a high school sophomore, is facing charges of aggravated murder and attempted murder in the killings, and prosecutors are seeking to try him as an adult, according to CNN affiliates WKYC and WJW.
In court documents filed by prosecutors, Richard Beasley, 52, of Akron, Ohio, is also alleged to have been involved in the killings. But he hasn't been charged yet specifically in relation to the case.
Beasley did plead not guilty this week to promoting prostitution charges -- an unrelated case -- and he was being held in lieu of $1 million bail, WKYC reported.
Rafferty's father, Michael, told WJW a week ago that his 16-year-old son had been "manipulated" and "corrupted," insisting that his son is a "mild-mannered gentleman."
The father also said that his son unwittingly dug the graves at Beasley's direction, WJW reported. The boy's mother said her son denied killing anyone and added that Beasley portrayed himself as "a chaplain" who gave food to the homeless.
Last week, another victim was identified as Timothy Kern, 47, of Massillon, Ohio, who died from gunshot wounds to the head and whose body was found in a shallow grave behind an Akron mall, authorities said.
The other murder victim has been identified as David Pauley, Noble County Sheriff's office dispatcher Kevin Macri told CNN on Saturday. The South Carolina man's body was also found last month in a shallow grave with a gunshot wound to the head, according to WKYC.
The investigation into the killings began the night of November 6, when a Noble County deputy sheriff responded to a call and came upon a "white, middle-aged man being treated for a gunshot wound to the right arm," according to Hannum.
The wounded man, who is from South Carolina and was not identified by police, told the sheriff he had answered an ad on the Craigslist website offering work caring for cattle on a 688-acre property.
He met with the two suspects and drove with them toward Stock Township. After being told a road was closed due to a landslide, the South Carolina man got out of the car to start walking toward the property, which he was told was nearby.
He told the sheriff that, while walking through a heavily wooded area, he then turned around "to see a gun pointed at his head. He deflected the gun and ran" -- getting shot in the arm while fleeing, the sheriff explained last month. The victim hid for seven hours in the forest before going to a house and requesting help, Hannum said last week.
Zach Kern, 19, told CNN last week that he last saw his father, Timothy, on November 12 after he had gone with another son for the job interview.
"He was all stoked about it," Zach Kern said of his father's feelings about the opportunity to work on the cattle farm. "My brother ... thought the whole situation was sketchy."
Zach Kern said his father, divorced and with three children, worked "odd jobs" including recently as a street cleaner in Canton. He said that his father saw his children daily, adding that the whole family is struggling to come to grips with his death.
"We're just trying to get through this," Zach Kern said.
In his last Facebook posting, dated November 10, Timothy Kern wrote: "Just got one of the strangest job offers. A good offer but strange. The job is to watch over 680 acres south of cambridge. Odd jobs and such but mainly just secure it. Trailer, utilities, salary. Drawbacks? No cell phone service, kids are up here, and i have to move this Sunday."
CNN's Ross Levitt contributed to this report.