LONDON—The late Prime Minister Sir Edward Heath would have been formally questioned for the alleged rape of an 11-year-old boy and the alleged indecent assault of a 10-year-old boy if he were still alive, according to police detectives who have spent two years investigating claims that he was a pedophile and serial sex attacker.

The investigation, which probed 42 allegations stretching from 1956 to 1992, concluded that there were seven alleged victims whose claims would have put Heath “under caution”—the equivalent of reading one their Miranda rights before questioning in the U.S. justice system.

The Daily Beast revealed two years ago that Ted Heath, who was the Conservative prime minister from 1970 to 1974, was named in a secret government dossier about an alleged VIP pedophile ring that was obtained by a senior Labour Party politician in the 1980s. Those allegations, amid claims of an establishment cover-up, never made it to a courtroom.

The new investigation into Heath examined 40 alleged attacks against boys, even though no charges could be brought against Heath, who died in 2005. Allegations that the Tory government of Margaret Thatcher helped cover up claims of a VIP pedophile ring emerged in 2015, at around the time the Heath investigation began.

Officers from the Wiltshire police force, who were placed in charge of the high-profile investigation, said there were “compelling and obvious” reasons to proceed to the formal interview stage as a result of seven of these accusations. The police said, however, that they were not in any position to conclude or even suggest that Heath was guilty of any crime because he is dead and cannot answer the allegations.

The police announced they would investigate old allegations against Heath in 2015 during a press conference given outside what had been his beautiful 12th-century home in the county of Wiltshire, where they called for additional witnesses to come forward.

That decision to go public attracted a storm of hostility from former friends and colleagues of Heath, who was head of the Conservative Party for a decade. Britain’s former head of public prosecutions, Lord Macdonald, said the report published by Wiltshire police on Thursday was purely an exercise in covering up their earlier mistake.

“It is no surprise at all that Wiltshire police should have concluded that they would have interviewed Sir Edward had he been alive,” Macdonald said. “This gives entirely bogus credibility to their investigation without meaning anything in forensic terms. The bar for interview is low, in most investigations as low as the police want it to be, and in the case of a dead man, virtually nonexistent. They are covering their backs at the expense of a dead man. Shame on them.”

Heath’s godson, his former private secretary, and old colleagues also gave interviews in a concerted effort to diminish the impact of this report on Heath’s reputation. They argue there is no evidence to prove Heath did anything wrong.

The police officers involved have spent months carrying out interviews and said they were able to discount most of the 42 original claims they received. Three of those came from the same man, using different identities. He has since been cautioned for wasting police time.

After interviews with the alleged victims, detectives interviewed hundreds of Heath’s former staff and officials, including drivers, protection officers, police, and yacht crews.

They were left with seven accusations about which they said they would have brought Heath in for questioning. In one of those cases, they said they had come across evidence that may have undermined the accuser’s account.

The report contained details of the six remaining accusations:

The first allegation dates back to 1961, when Heath was a minister in Harold Macmillan’s Conservative government. A man, who was 11 years old at the time, said he was raped and indecently assaulted during a paid sexual encounter in a private home.

Another man, who was 10 in 1962, said he was assaulted in a public place during a chance encounter with the Member of Parliament. Two years later, when Heath had been promoted to secretary of state for industry, another man says he was indecently assaulted during three paid sessions at the age of 15.

In 1967, when Heath was leader of the Conservative Party, a man who was 15 at the time says he was indecently assaulted after bumping into Heath in a public building. There were no allegations that met the threshold of interview while Heath was the prime minister in the early 1970s.

In 1976—a year after he was replaced as Tory leader by Margaret Thatcher—a fifth man says Heath indecently assaulted him over his clothing at a public event.

The most recent allegation dates to 1992. An adult male prostitute claimed he was indecently assaulted after consent was withdrawn during a paid encounter at a hotel.

"Sir Edward Heath was an extremely prominent, influential, and high-profile person who was arguably one of the most powerful people in the world commensurate with the political office he held,” said Wiltshire Chief Constable Mike Veale. “The allegations against him were of the utmost seriousness and from a significant number of people.”

During a press conference designed to refute allegations that the officers had embarked on a witch-hunt, he said: “I hope people will understand that, given these circumstances, it would be an indefensible dereliction of my public duty as a chief constable not to have investigated such serious allegations.”

Veale said he hoped that his investigation would prove to be “a watershed moment for people and victims who have suggested or implied there has been a state cover-up.”

For some suspicious minds, this report and the fallout will undoubtedly serve to do the opposite. Despite interviewing at least six witnesses who made allegations against a former prime minister, members of the British elite have been quick to dismiss the investigation.

Lord Hunt of Wirral and Lord Armstrong of Ilminster, who were Cabinet secretary and senior aide to Heath while he was PM, issued a joint statement attacking the investigation.

"The Wiltshire police report is profoundly unsatisfactory because it neither justifies nor dispels the cloud of suspicion,” they said.

Another former Conservative minister and friend of Heath, David Mellor, went even further during an appearance on Sky News. “This is a shocking and dreadful thing,” he said. “He was a distinguished public servant. Why should his memory be polluted?”

At the end of 2014, Scotland Yard detectives announced that a witness had made serious sexual-assault allegations against senior politicians that they believed to be “credible and true”—those allegations by a man known as “Nick” have since been discredited.

In addition to the new allegations against Heath, a review of old case files carried out during the inquiry found that Heath was named as an abuser by an alleged victim in 1989, but Wiltshire police did not pass on the information to the Crown Prosecution Service.

One of the major lines of inquiry came through five allegations that Heath had committed offenses on yachts between 1964 and 1986. None of the eight crew members interviewed by police corroborated that these attacks had taken place.

Former local newspaper editor Don Hale told The Daily Beast that he was shown an article on Heath organizing weekend sailing trips for boys on his yacht that appeared in Magpie, the magazine of the notorious Pedophile Information Exchange underground organization. The clip was part of the government dossier on Heath that he says was handed to Barbara Castle, a Labour Member of the European Parliament at the time.