Donald W. Hoffman, 41, was ordered held on $10 million bail at his arraignment.
Hoffman's alleged victims include his roommate, Gerald Lee Smith, 65, and Billy Jack Chatman, 55, Freelin Hensley, 67, and Darrell E. Lewis, 65. The four men, who knew each other, were found dead in their homes Monday and Tuesday.
Investigators said Hoffman came to police Tuesday with information on two of the deaths and led them to the other bodies. While police said autopsies would determine what killed the victims, authorities had said all four had apparently been beaten.
Hoffman has a record of crimes like passing bad checks and burglary and theft. Neighbors described him to the Columbus Dispatch as the "town drunk."
"He was nice to me and my kids," said Lola Pflider, who lived in the apartment next door to Hoffman and Smith.
Valerie Smith-Malone said her uncle had a longtime drinking problem. Relatives described all four victims as men with injuries, illness or alcohol addiction.
"All these guys were sweet guys," Smith-Malone said.
Bucyrus, a city of about 12,000 midway between Lake Erie and Columbus in north-central Ohio, is usually a quiet place. Officials planned to hold a vigil Thursday afternoon to pray for the victims, their families and Bucyrus.