Channel 7’s Sunday Night program has named a man who was at one time one of the most-wanted fugitives by the FBI.

Christopher Bernard Wilder, known in the United States as The Beauty Queen Killer, abducted and raped at least 12 women, killing nine of them, during a six-week cross-country crime spree in the US in early 1984.

Wilder lived in Australia from birth until 1969 and was residing on Sydney’s northern beaches at the time of the Wanda murders. 

Police files obtained from 1960s reveal that Wilder was named as an official police suspect.

Read more: Files to be reopened on unsolved Illawarra murder cases

Retired Detective Inspector Ian Waterson was in charge of the Wanda Beach cold case, and he believes Wilder is the number one suspect in one of the nation’s most baffling crimes.

“In my mind, it would have to be Christopher Wilder because there are so many signs to this guy that point to his sexual deviancy, his propensity for violence and [he] was around in Sydney at the time, hung around the beaches,” said Waterson.

On a summer’s day in January 1965, Marianne Schmidt and her friend, Christine Sharrock, both 15, disappeared until their bodies were found in a shallow grave in the sand dunes at Wanda beach.

Despite countless theories and leads over the past five decades, the “Wanda Beach Murders” remains one of Australia’s most infamous unsolved cases 53 years on.

The Sunday Night program has revealed how Wilder escaped scrutiny from the police even though his name had been put forward by his wife.

Wilder married in 1968 but his wife left him after one week because of his violent nature and raised her suspicions with authorities. 

Read more: Blue car could hold key to murder of Rachelle Childs

Police took months to follow up the lead and missed the opportunity to interview Wilder before he immigrated to America in 1969, at the age of 24, and settled in Miami.

His case file is marked “Suspended” as a result of having slipped investigators.

The Schmidt family were never told of the existence of Wilder during police investigations.

In the United States Wilder would start on a path of horrific crimes that would become increasingly brutal and brazen. 

In 1984 a bloody six-week manhunt ensued as Wilder crossed the country kidnapping, assaulting, raping and murdering young women before finally shooting himself in the heart in a showdown with police.

The Sunday Night television program interviewed a number of former police officers in Australia and the US who all held the view that Wilder would be a very strong suspect in the Wanda murders given he lived in Sydney at the time.

Marianne’s younger brother Bert told Sunday Night the family were never told about the Wilder lead.

“That’s crap – what did the cops do?,” an upset Mr Schmidt says when shown the police document.

“Wife goes to the cops and the cops do nothing for eight months.

“I just can’t believe that – that’s ridiculous.”

Marianne’s other younger brother Hans, an Innisfail photographer, told the Cairns Post in 2016 that he doubted police would ever catch her killer.

“Find the guy and I’ll pull the trapdoor myself,” said Mr Schmidt, who was just 13 at the time of the murders.

“I don’t believe they will solve the crime, it has been too long now.

“But obviously some people know the perpetrator because you’re not going to keep this a secret to that extent.”

Marianne Schmidt’s sister Trixie Falzon told a magazine in 2010 the unsolved murder had ‘‘left a hole in my heart that I’ve never gotten over’’.

‘‘I’d ask her killer ‘why did you do it?’,’’ she said. ‘‘They were innocent young women.’’

NSW Police is using new scientific techniques which may finally bring some closure to the Schmidt and Sharrock families.

A NSW Police spokeswoman urged anyone with information that could help solve the crime to come forward.

“As with all unsolved homicides, we continue to appeal for information from the public. 

Anyone who has information that may assist is urged to contact Crime Stoppers on 1800 333 000.