Trevor Marriott wants the truth, but Scotland Yard says he just can’t handle it. Literally.

The retired police investigator has told the Los Angeles Times he is hot on the trail of what’s been called the world’s coldest case — the search for “Jack the Ripper” – but British authorities’ decision to withhold evidence dating back to the time of the murders 123 years ago has broken his stride.

So what could today’s “Yard” possibly have to hide?

To start, their faces. At a hearing late last month, an official identified as “Detective Inspector D” explained the decision from behind a blurred sheet. He said that giving the public access to the Victorian-era records of the investigation could have a chilling effect on police informants today. The detective also warned of reprisal attacks against the kin of those who cooperated with investigators during the terror of 1888.

“Look at one of the world’s best-known informants, Judas Iscariot,” he said, according to The Daily Telegraph. “If someone could draw a bloodline from Judas Iscariot to a present-day person, then that person would face a risk, although I know that seems an extreme example.”

Marriott rejects that argument and says he just needs a little more evidence — some of it perhaps couched in the dusty files held under lock and key at Scotland Yard — to confirm his suspicion that the real “Jack the Ripper” was a German sailor named Carl Feigenbaum.

According to records, Feigenbaum was in the Whitechapel area at the time of the murders and would eventually land in the U.S., where he was executed in 1896 after being convicted of killing his landlady.  Marriott wrote a book in 2007 to this effect, much of it sourced from statements made by Feigenbaum’s American attorney.

Police in London interviewed more than 2,000 people and officially investigated about 300 suspects during their original ”Ripper” probe. But the murders, five confirmed, remain an unsolved mystery and have achieved a certain cult status among glory-hunting sleuths.

Another retired London homicide detective, Robert Milne, has come forward declaring that the killer was actually a Polish immigrant named Severin Klosowski. Milne says Klosowoski’s background as a surgeon accounts for the precise wounds suffered by victims.  He presented his findings at an International Association for Identification conference this summer in Milwaukee.

Milne told the Toronto Star that his fellow “Ripperologist,” Marriott, is mistaken and that  the killer was a “neighborhood marauder, not a trans-European worker such as a sailor.”

With London police holding steady in their refusal to open up the books, this kind of debate — and the cottage industry that gives it life – is unlikely to go away anytime soon.