Anthony Sowell, the rapist and suspected serial killer, appeared in court today to answer five charges of aggravated murder, as police searching his home found a further four bodies and a human skull.

The latest discoveries bring the total number of human remains to emerge from Sowell's ramshackle inner city property in Cleveland, Ohio, to ten — with the skull suggesting a possible eleventh victim.

Police have dug up four rotting corpses from shallow graves in his back garden and found other remains hidden in the basement, in a third-floor living room and in a crawl space under the house eaves. The skull was wrapped in a paper bag in a bucket.

Today Sowell appeared this morning before Judge Ronald Adrine in Cleveland Municipal Court on five counts of aggravated murder.

He looked straight at the judge as Assistant County Prosecutor Brian Murphy asked that he be held without bond and described him as an “incredibly dangerous threat to the public”.

He added that Sowell was facing the death penalty.

Kathleen DeMetz, a public defender representing Sowell, asked that bond be set, noting that her client has a pacemaker for a heart condition.

Judge Ronald Adrine refused, ordering Sowell to be held without bond. He said that the charges were the most serious allegations he had ever seen.

The latest four bodies were discovered by a police digger, after cadaver dogs were unable to pick up a scent due to strong winds yesterday.

A spokesman for the Cuyahoga County Coroner said that the bodies “could have been there anywhere from weeks to months to years”.

Fearing that there may be other victims further afield, officers were today due to extend their search of vacant terraced properties within four hundred yards. Mr Sowell did not have a car and would have had to take a bus to travel, according to city police chief Michael McGrath.

Fire fighters will spend the day tearing apart the walls and ceilings of Sowell's property in search of any other niches where victims might lie hidden.

"I would like to believe there is nothing else there, but we won't know until we search everything," said Mr McGrath.

Some relatives of missing people kept vigil in the street as police stretchers carrying bodies came out of the property on Imperial Avenue. "I just hope that it isn't my mother and I hope that she come home," said the daughter of Nancy Cobbs, who vanished in April.

Police have been called to Sowell's house several times, most recently two weeks ago when a naked woman fell out of a first floor window, suffering cuts and scrapes. She declined to press charges.

Antoinnette Dudley, 29, a neighbour in the crowd that last night held hands and prayed outside Sowell's house, said that she had been aware of a terrible odour all summer as though something was dead. She said that, in his rare appearances outside the house, she had seen Sowell sitting on his porch drinking beer. "I didn't think he was that sick," Ms Dudley said.

There were complaints that the authorities had been slow to act on the stench that has been emanating from Sowell's home for years.

The owners of Ray's Sausage, a nearby cheese and sausage factory, replaced their sewer pipes and grease traps after repeated complaints to public health officials about the foul smell on the street corner.

City Councilman Zack Reed, whose mother lives a block away, said that he called the health department in 2007 after a resident told him about an odour that “smelled like a dead body”.

He said that he and other community leaders wanted an investigation into whether police and health inspectors missed signs that could have tipped them off to the bodies earlier, and even saved lives.

“We don’t want to point fingers, but clearly something could have been done differently,” said Councilman Reed.

Others were concerned that the justice authorities, who had been monitoring Sowell regularly as a registered sex offender, had delayed and missed vital clues.

Sowell, 50, was released from prison in 2005 after serving 15 years for rape. Scratching a living through begging and scrap metal dealing, he remained under the supervision of the local sheriffs who would drop by to check up on him quarterly under the terms of his parole. They did not enter his house.

The last visit they made was on September 22, just hours before a woman went to police to complain that Sowell had invited her to house for a drink, then become enraged, choking her with an extension cord and raping her.

It was not until last Thursday, October 29 - 37 days later - that officers followed up her complaint by visiting Sowell's property, where they uncovered the first bodies. Sowell was arrested on Saturday.

Of the first six bodies to be found, all were black women and five had been strangled.

Mr McGrath said that he could not assume the women who wound up dead in Sowell's house had gone there against their will. "I have to believe at this point all these victims voluntarily went to this residence," he said.

Sowell was charged with five aggravated murders, rape, felonious assault and kidnapping, and was appearing in court in Cleveland today. Other charges are set to follow.

"I can imagine how families feel who have reported a missing person, and anxiety that they are going through," said Frank Jackson, the Mayor of Cleveland. "We want to assure them as soon as we know something they will be the first to know."

America's biggest killers

Jeffrey Dahmer was convicted of 16 murders from 1978 but may have killed more. He kept heads, skulls and body parts in his apartment for sexual gratification

Ted Bundy confessed to the rape and murder of 28 women in six states but he is suspected of killing many more. Executed in 1989

Gary Leon Ridgway killed at least 48 women in the "Green River" killing spree in the 1980s. He strangled most of them

Belle Sorenson Gunness was one of America's most prolific female serial killers. Thought to have killed more than 40 people from the 1880s

John Wayne Gacy Neighbours complained of a stench coming from the house of the children’s party clown throughout the 1970s. Police found the bodies of 29 boys under his Chicago home

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