LONDON, England (CNN) -- Debris excavated from the basement of a former children's home is being sent to laboratories for further examination, police said Monday.
Forensic teams spent the weekend searching the building on Jersey, an island between England and France, after a fragment of a child's skull was found late in February.
Cadaver dogs have found six "hits," locations where a body or body parts may have be buried, said police press officer Louise Nibbs.
Jersey Deputy Police Chief Lenny Harper said Monday the weekend search did not turn up anything obviously related to the child abuse accusations.
Since the skull was found under a stairwell in the building, there have been more than 160 allegations of child abuse there dating back to the 1960s, authorities say.
Harper said excavation of the grounds found "a fair number of bones," but none that an anthropologist said appeared human.
Even the skull fragment may prove to be a false lead, he told reporters Monday. "It could turn out to be a red herring. All we know is that it's human and that of a child."
The case has placed a massive burden on the resources of the British crown dependency located 14 miles off the coast of Normandy.
Twelve detectives arrived from England to join the 25 investigators already assigned to the case, Harper said. Two anthropologists, an archeologist, a dog handler and seven people "working in various jobs" are also involved, he said.
The work is painstaking. Harper predicted the excavation alone could continue for another month. "It is a vital ingredient of the investigation that we take our time and are not under pressure to rush it," he told reporters.
For now, the investigation is focusing on the building, which opened in 1867 and housed up to 60 children at any one time. It underwent several renovations and closed in 1986 only to reopen as a youth hostel in 2004.
Possible clues to the alleged abuse include writing found on a wall that "refers to somebody being bad," Harper said. "We have no idea at the moment who put it there or, indeed, how long it's been there."
Police say much of what they are finding, including shackles, matches accounts given by witnesses.
Several former residents allege they suffered physical and sexual abuse in a storeroom. Police suspect there could be four bricked-up chambers underground. Watch how the abuse investigation has grown »
Several alleged victims have talked about abuse occurring in a large concrete trough in the basement, which was originally the first floor of the building.
So far, authorities have compiled "well over 40" suspects who are alive, and a number of others who are dead, he said.
The investigation has taken officials to Australia, where Harper said they had obtained "significant and valuable evidence," and to Thailand, Germany and the British mainland.
Some of those who have reported abuse have taken their complaints to the news media.
"There was one occasion, in the sick bay, where I was made to fondle another boy -- if you didn't, you were threatened you wouldn't come out alive," said Carl Denning, who said he was taken to the home at the age of 5 and said one of his friends committed suicide after being raped there.
"You'd go to bed at night, sleeping, and all of a sudden your arms would be held down and the next thing you know you're getting raped," recalled Peter Hannaford, who spent the first 12 years of his life there. "You were subject to constant abuse. ... It was every night, and you were scared to go to bed."
Stuart Syvret, a local politician, told CNN the building had long been known "as a place where young boys were punished severely, where they suffered."
He alleged a "long-established culture of covering up alleged abuses" -- a claim the local government denies.
Graham Power, the chief police officer on Jersey, has promised a thorough investigation.
The investigation began in 2006, when police were alerted to the possibility that pedophiles had worked at the institution. That led to the discovery of the skull fragment.
The institution -- called Haut de la Garenne -- housed wards of the state -- primarily neglected and abandoned children. A remand wing housed children who had been convicted of crimes.
The allegations mar the carefully cultivated image the island's elite have tried to project. Jersey's beaches have made it a big tourist destination, and its offshore banks have made it a tax haven and a playground for the rich.
Eleven miles long and 9 miles wide, the island is populated by about 80,000 mostly affluent residents. Heavily influenced by the French, the largely autonomous island has its own legal system and its own currency. London manages only its defense and foreign policy matters.
Jersey is governed by senators and deputies who sit in the legislature -- called the Assembly of States -- which is viewed by some as an old boys' club that aggressively guards the island's image. E-mail to a friend
CNN's Nicola Goulding, Paula Hancocks and Roger Clark contributed to this report