The serial child killer and paedophile named a key suspect in the search for Madeleine McCann was in Portugal when she vanished, it has been claimed.
German paedophile Martin Ney was jailed for life in 2012 for abducting and murdering three children, and sexually abusing dozens more.
Goncalo Amaral, the Portuguese cop who first led the hunt for Madeleine, revealed last week that police were probing a "German paedophile who is in prison".
The 48-year-old paedophile was working for a church on a project for the homeless in Portugal when Madeleine disappeared, according to new claims.
Ney is also now a bombshell suspect, with the killer looking extremely similar to the photofit of a man who was seen acting suspiciously before Madeleine disappeared from the holiday apartment more than 12 years ago.
The paedophile was familiar with the Algarve after being a regular traveller to Portugal in the 1990s.
'PREPARING THE END OF THE INVESTIGATION'
The timings raise the possibility Ney murdered a youngster every three years — 1992, 1995, 1998, 2001 and 2004, before Madeleine vanished in May 2007.
He was jailed for killing three German kids — Stefan Jahr, 13, in 1992, Dennis Rostel, eight, in 1995, and Dennis Klein, nine, in 2001.
He is also suspected of the murder of a child in Holland in 1998 and another in France in 2004.
Following the opening of the Madeleine case, Amaral revealed on Australian TV that British cops were focusing on a jailed German.
He claimed it had "one investigation line" — and slammed British authorities for only looking at one possibility.
Mr Amaral said: "Detectives are preparing the end of the investigation, with a German paedophile who is in prison right now."
Last week Portuguese newspapers also reported that British Metropolitan Police detectives had provided information about a foreign paedophile.
A recent Netflix documentary on the case focused on a suspect who targeted British holiday-makers' apartments in Praia da Luz in 2007.
The man, who wore a surgical mask and had a foreign accent, preyed on children.
Scotland Yard is known to have been in contact with German detectives over Ney.
Well-placed sources also confirmed yesterday Ney's internet chatroom history — using the name GerdX — had been probed.
In a chilling post from 2002 he wrote: "I bought a camouflage suit to jump out of the bushes in children's playgrounds if a beautiful boy goes past."
Ney's known victims are boys, but clinical psychologists say gender is often unimportant to paedophiles. Private detectives working on behalf of the McCanns also previously looked into Ney, whose horrific crime spree is believed to have started in Germany in 1992.
JAILED FOR LIFE
Police know Ney visited Ecuador in 1993, Peru in 1995 and Portugal the following year. He has also made repeated trips to Holland and Denmark.
He was finally arrested in April 2011 after a massive police operation.
He confessed to the three German murders and sexually abusing 40 other children, and was jailed for life.
However, during interviews, he denied involvement in any other child abuse or missing children's cases.
Despite this, he was suspected of murdering Nicky Verstappen, 11, who vanished from a holiday camp in Brunssum, Holland, in 1998.
Last year it was also reported Ney confessed to a cellmate to the 2004 killing of Jonathan Coulom, who was kidnapped from a camp in western France.
British officers are now believed to be trying to work out if Nye was in the Algarve at the same time Madeleine disappeared.
KIDS ON TRIPS TAKEN AND KILLED
Martin Ney targeted children in school dorms and holiday camps — while wearing a mask and dressed in black.
His first known murder victim, Stefan Jahr, 13, was taken at night from a boarding school in Scheebel, Germany, in 1992.
A string of boys on camping trips were also sexually abused by him, with victims describing him as the Masked Man.
In 1995, Ney snatched Dennis Rostel, eight, from a camp in Schleswig-Holstein, Germany. His body was found in Denmark.
Ney also killed Dennis Klein, nine, who vanished on a school trip to Lower Saxony, Germany, in 2001.
He was also convicted of sexually abusing at least 40 kids and is suspected of two other murders.
- Additional reporting by news.com.au