Donald Hoffman has been in custody since Tuesday, when police say he walked into the department alone and provided officers with information that led to two of the bodies. Two others had been found a day earlier.
Hoffman, 41, had been jailed on a probation violation until he was charged in the deaths Thursday. A judge ordered him held on $10 million bond - $2.5 million for each alleged slaying - following a recommendation from the prosecutor, who said Hoffman's criminal record includes assault, menacing and theft.
The county coroner said Thursday the men were beaten, strangled or both.
"There's no doubt that the defendant has been accused of a series of horrific crimes. If he did commit those crimes, he poses a threat to basically every citizen in this community," Crawford County Municipal Court Judge Sean Leuthold said.
The judge appointed a lawyer for Hoffman. A message was left for that attorney.
Hoffman appeared via video feed from jail, seated in an orange jail outfit with his arms crossed. He spoke only to acknowledge that he understood an explanation of how the case would proceed. Authorities said the case could be presented to a grand jury Monday.
More than two dozen relatives of the victims attended the hearing, some wiping tears as the judge read the charges. Most left without commenting, but a few made statements of grief, anger or confusion about why their loved ones might have been killed.
The bodies of 55-year-old Billy Jack Chatman and 67-year-old Freelin Hensley were discovered Monday at their homes in this city of 12,000 residents about 65 miles north of Columbus. On Tuesday, the bodies of 65-year-old Darrell Lewis and 65-year-old Gerald Lee Smith were found.
The Crawford County coroner, Dr. Michael Johnson, said Thursday that Smith and Hensley died from being strangled with a cord and beaten in the head. Lewis died from strangulation with a cord, and Chatman died from head trauma.
Bucyrus police Chief Dave Koepke said Thursday that investigators are pursuing leads and awaiting preliminary autopsy results as they try to establish a timeline for the slayings and determine the motive.
Koepke earlier noted at least one gruesome commonality: "All the victims suffered." He said each man had trauma above the shoulders, but he wouldn't give specifics.
Brenda Lauthers, a Bucyrus resident whose brother was among the slain men, said that she found a frying pan in a bathroom sink near his body and that the family of another victim told her that man apparently was hit with a hammer. Police refused to discuss those kinds of details, citing the ongoing investigation.
Crawford County Sheriff Scott Kent, whose office is assisting local police, has said Hoffman gave some information as to why the killings occurred, but authorities haven't released details.
The town is unaccustomed to violent crime but doesn't shy from discussing what residents and police describe as prevalent drug problems, especially with heroin.
At a Thursday prayer service attended by about 100 people, including some of the victims' relatives, local religious leaders talked about overcoming addiction and finding forgiveness and peace.
Associated Press writers Mitch Stacy and Jennifer Smola contributed to this report from Columbus, Ohio.