(CNN) -- Police discovered a seventh body at the Cleveland, Ohio, home of a convicted rapist arrested this weekend after the decomposing bodies of women were unearthed at his residence, a source close to the investigation told CNN.
The source, who was not authorized to speak on the record, did not give the gender of the seventh body found at the home of Anthony Sowell, 50. The source did not say exactly where the body was found at the residence.
Cleveland police have scheduled a news conference for 6 p.m. (ET) Tuesday to discuss the investigation.
Police arrested Sowell on Saturday, two days after discovering the decomposing bodies of five females inside his home and another woman's body outside the house.
Authorities found the first two bodies while trying to serve an arrest and search warrant on Sowell related to a sexual assault investigation, and an intensive search began. Sowell was not home at the time; officers found him after a tipster told them of his whereabouts.
The decomposing bodies of the women, all of whom were African-American, could have been lying where they were found for "weeks, if not months or years," Cuyahoga County Coroner Frank Miller III told CNN on Saturday.
All six deaths were ruled homicides, Lt. Thomas Stacho of the Cleveland Police Department said Monday, with five of the deaths due to strangulation.
About a month ago, a woman accused Sowell of rape and felonious assault, Stacho noted last week. Investigators obtained the warrants that set off the search after the "cooperation of the victim," he said.
Officers serving the warrants Thursday discovered the badly decomposed remains of two bodies on the third floor of the house, he added. A subsequent search revealed what appeared to be a freshly dug grave under the stairs in the basement. On Friday, investigators returned to the house, dug up the grave and found a third body, Stacho said.
A further search of the house and property found two more bodies in a crawl space and a sixth body in a shallow grave outside the home.
A source confirmed to CNN on Tuesday that at least one more body had been found at the home.
Five different burial methods were used on the victims, and the bodies were in varying states of decomposition, said Miller, which made it difficult to determine the ages of the victims. He added that the states of the bodies made it hard to tell how long they had lain in the makeshift graves.
"It's really very difficult to tell," Miller said. "It's been some time. I would say probably at least weeks, if not months or years."
Stacho said Sowell makes his living as a "scrapper."
"He walks around and picks up scrap metal and takes it to junk yards to make a few pennies," he said.
Sowell was convicted of a 1989 rape and was imprisoned from 1990 to 2005, Stacho said.