Because at least four agencies are working on the case — APD, the Paulding Country Sheriff's Department, the Duluth Police Department and the Georgia Bureau of Investigation — Pennington was not specific about what the similarities or possible motives were.
Pennington said Schaller, who was found dead at his home on Dutch Valley Road in northeast Atlanta, was strangled.
Officials in Duluth and Paulding County have not revealed how McKinney and Abney died.
"They were killed. I look at all murders as being brutal and heinous," Pennington said on the method of death.
Pennington did say that each of the victims might have met Belcher in some social setting.
"We don't know if he knew these individuals or if they were friends," Pennington said.
Pennington said Belcher is also a suspect in a February robbery and kidnapping that occurred at Defoor Village Court. In that case, one person was locked in a closet, while another person was forced to withdraw money from an ATM.
The chief said detectives are reviewing all open homicide, robbery and assault cases to see whether there is a link to Belcher.