A suspected serial killer named Scalp Hunter is believed to be the key to at least three other murders.
John Sweeney, 66, is already serving a life sentence for two grisly murders.
Now his name is linked to an Interpol objection over the remains of 22 women found on the continent.
Operation Identify Me involves three murders in the Netherlands, where Sweeney worked in the 1990s.
They conform to his method of beheading victims and disposing of corpses in waterways.
Former Met detective Colin Sutton urged Dutch police to look into the link.
He said: “The Met will have a lot of information about his movements. You will be happy to share this.
“The striking resemblance of these murders is such that efforts should be made to eliminate or charge him – and I am sure that will happen.”
Liverpool-born Sweeney was sentenced to life in 2011 for murdering US-born Melissa Halstead, 33, in Rotterdam in 1990 and mother-of-three Paula Fields, 31, in London in 2001.
He also attacked the former Delia Balmer with an ax at her home in London in 1994, but she survived.
He then fled abroad.
Sweeney earned his nickname Scalp Hunter due to one of his many gruesome sketches.
He refused to speak to the police about his killings, merely telling them he had 30 to 40 relationships while working on construction sites in Europe.