An entomologist hired to study maggots found on the bodies discovered in the home of Cleveland's alleged serial killer said today it would take him weeks to determine when the victims died.
Joe Keiper of the Cleveland Museum of Natural History told ABCNews.com that he was asked by the Cuyahoga County Coroner's Office to inspect the blow fly larvae feeding on the corpses found at Anthony's Sowell's home in hopes of establishing a time frame for the deaths.
"Depending on the type and number of insects on a body, I might be able to get an estimate on the postmortem interval, or the time passed between death and body discovery," said Keiper, adding that he is one of only 20 U.S. forensic entomologists.
Keiper looks primarily for the larvae of blow flies, a species of insects that he said is one of the most important drivers of decomposition. Their growth rates are also predictable, Keiper said, making it easy to figure out when they landed on a decomposing body.
"The odor of decay occurs immediately," Keiper said. "Blow flies pick up the gases omitted by bodies during decomposition at such a high speed that these insects are truly the first responders on a crime scene."
Keiper said he first went to the coroner's office to examine and collect entomological evidence from the first bodies that were found in convicted rapist Sowell's home but later returned to do a "body-by-body investigation."
Calling Sowell's home "infested," Keiper declined to go into more detail.
Typically spending a month on each case, Keiper predicted that because of the sheer number of bodies in the Sowell case, his entomological evidence could take months to process.
Still, Keiper said, this could be the first time that insect research is the only evidence to support a timeline of a crime.
"I've worked 32 cases, but there were only a couple of them where entomological evidence played a big role," he said. "Usually, my research is just stacked up with eyewitness accounts.
"My work on this case might be the only chance to get an accurate timeline."
As funerals begin for several of the victims of the alleged serial killer, investigators work to identify the remaining bodies and searc for more in nearby homes.
All but one of the 11 female victims found dead in and around Sowell's three-story Cleveland house have been identified.
Cleveland authorities released the identity of the 10th victim Wednesday night, which was complicated because only her skull was found -- in a bucket in Sowell's basement.
Leshanda Long, 25, had been missing since August 2008, authorities said, but had never been reported as a missing person.
Sowell, 50, was charged with five counts of aggravated murder after authorities looking to question him for a reported rape last month came upon an even more gruesome finding: a horrible stench of rotting bodies that eventually led them to corpse after corpse in the home.
Sowell, who was ordered by a Cleveland judge to be held without bond last week, was on suicide watch and was described by a prosecutor as an "incredibly dangerous threat to the public."
Suspect Could Face Death Penalty
If convicted, Sowell could face the death penalty.
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.
Sowell Investigation Continues
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.