Able to enter the home because of a search warrant, authorities first found two bodies, then later three, and, eventually, a total of 11. The bodies were found littered throughout the home, some in shallow graves in the backyard, others in crawl spaces. Authorities later went on to tear apart the home's walls in search of additional bodies.
Neighbors were furious that authorities, who had Sowell, a convicted rapist, on their list of sex offenders to monitor, did not uncover the bodies sooner, especially after warnings of the smell wafting from the home.
But officers were unable to enter the home initially because they did not have a search warrant, authorities said. Instead, they would knock on his door to make sure he was home. Sowell was last visited by authorities Sept. 22.
Sowell was released in 2005 after serving 15 years in prison for the choking and attempted rape of a 21-year-old woman in 1989.
Family members of the victims have also expressed their frustration with the Cleveland Police Department, some of whose officers were reluctant to take the missing persons reports seriously, because many of the women were known drug users.
Sandy Drain, whose niece was identified as one of the bodies found in Sowell's home, told The Associated Press that she believes police looked at her missing family member as "Oh, just another drug addict gone."
But detectives said they are retracing Sowell's steps since his release from prison four years ago, following his trail back more than 30 years, from when he served in the Marines from 1978 to 1985, FBI spokesman Anthony Scott told The Associated Press.
Authorities are looking into unsolved crimes around the bases where Sowell was stationed: Parris Island, S.C.; Cherry Point, N.C.; Okinawa, Japan; and Camp Pendleton, Calif.
Police in Coronado, Calif., near Camp Pendleton, told the AP that a woman contacted them after seeing Sowell's mug shot on TV. She said she was sure he had raped her in 1979.
Officers were unable to confirm her story because records from 30 years ago have been thrown out, Coronado police commander Jesus Ochoa told the AP.
The city of East Cleveland is also taking a second look at three unsolved murders in 1988 and 1989 to determine whether Sowell might be a suspect.
The Associated Press contributed to this report.