(CNN) -- A registered sex offender has been indicted on 85 counts -- including aggravated murder, rape and kidnapping -- in the deaths of 11 women whose bodies were found at his home, authorities said Tuesday.
In addition, Anthony Sowell, 50, is charged with "brutalizing" three women and raping two of them, Cuyahoga County Prosecutor Bill Mason said.
Prosecutors are seeking the death penalty against Sowell, Mason said. Sowell is scheduled to be arraigned Thursday.
Sowell is now charged with 11 counts of aggravated murder with a "mass murder specification," meaning multiple people were killed in a similar fashion, Mason said. He also is charged with abuse of a corpse, kidnapping and tampering with evidence.
The indictment also alleges that Sowell assaulted women on December 8, 2008, and on September 22 and October 20 of this year.
The September and October victims were raped, and the other woman was punched and choked before she escaped, Mason said. Sowell's charges in the incidents include attempted murder, rape or attempted rape, kidnapping, robbery and felonious assault.
Sowell already faced charges in the September 22 rape and has pleaded not guilty.
On October 20, neighbors reported seeing a naked woman fall from the second floor of his house. Firefighters responded and later notified police. But the woman told officers she fell off the roof while she was at the home "partying," police said earlier. No charges were filed at the time.
Mason said, however, that the 51-year-old woman had been invited to Sowell's home and left, but was lured back in. After being choked and raped, she attempted to escape out a second-floor window as Sowell tried to pull her back in. When he was unsuccessful, he pushed her out, and she lay unconscious in an alley for a while before he pulled her back in the house.
Sowell threatened his victims and warned them not to contact police, Mason said.
It's possible there are other victims, he said, and he urged anyone who has not come forward to do so.
Sowell "knew what he was doing was wrong at the time he was doing it," Mason said.
As of last month, Sowell was on suicide watch at the request of his public defender, Kathleen DeMetz. She had said a psychiatric evaluation of Sowell had been ordered but was unlikely to happen until after an indictment was filed.
Cuyahoga County Sheriff Bob Reid said Tuesday that Sowell has been a "model prisoner," is kept in an isolated unit and has declined visitation requests.
All of the 11 victims were African-American women, authorities have said. Most of them were strangled by ligature -- which could include a string, cord or wire -- and at least one was strangled by hand, officials said. Seven still had ligatures wrapped around their necks.
All that has been found of one woman is a skull that was wrapped in a paper bag and stuffed into a bucket in the home's basement.
Sowell served 15 years in prison for a 1989 attempted rape and was released in 2005. He was required to register as a sex offender.
After the 11 victims were found, police in mid-November used thermal imaging in an attempt to see whether any additional human remains were on the property. They dug certain areas by hand. No more were found.
Police and the FBI have said they are looking at the unsolved murders of three women in East Cleveland to determine whether there are similarities with the remains found at Sowell's home. The inquiry continues, Mason said Tuesday.
Police in Coronado, California, have said they are attempting to determine whether Sowell is linked to a 1979 rape there. Though the statute of limitations has expired, authorities said they would like to provide closure to the victim.
Neighbors and police have said that women were seen at Sowell's home from time to time and that he would offer them alcohol. Police said he also might have offered them drugs.
In the September assault, the 36-year-old woman told police that she encountered Sowell while walking in his neighborhood and he took her back to his home, where he became violent and raped her, according to prosecutors.
"While raping her, he strangled her with a cord until she lost consciousness," authorities said in a statement. "When she regained consciousness, he let her out of the house."