Police Capt. Rich Lockhart would not say what led police to connect the killings to a single person; the crimes have not been linked forensically. Authorities previously had said they thought the killings were related, though they had not theorized the slayings were the work of one person.
Police were working with the FBI to develop a profile of the killer.
One of those slain was found in July, but five others have been discovered since Thursday — including those found after someone calling 911 told police where to look.
All the bodies were discovered on vacant lots or near vacant houses or apartments in an area east of downtown where drug dealers and prostitutes were known to congregate.
Lockhart said police were looking for similarities between the victims and the crime scenes. Police have not said how the victims died; autopsies were under way Monday. Few details have been released about the victims, four of whom have been identified.
"Some were engaged in high-risk lifestyles," Lockhart said. He did not elaborate.