Fingerprints of a British barman accused of the murders of two teenage girls on the Costa del Sol match those of the so-called "Holloway Strangler", police sources have told the BBC.
King and Bromwich are one and the same say police
Tony King, or Tony Bromwich as he was then known, was convicted of a number of sexual assaults on women in London 17 years ago.
King, 38, who is originally from Holloway in north London, is being held in a Spanish jail, in connection with the deaths of the two young women.
Spanish police sources claim King has admitted killing 17-year-old Sonia Carabantes last month and 19-year-old Rocio Wanninkhof in 1999.
King has reportedly released letters in Spanish and English from prison in Malaga, apologising to the mothers of the two teenagers and begging their forgiveness.
King has apparently apologised to the victims' families
He says he has confessed everything in the hope they do not have to suffer any more.
The killings have caused outrage in Spain.
The murder of Miss Carabantes has dominated the Spanish media since she disappeared on 14 August while returning home from a fiesta.
Her body was found five days later.
She had been strangled, beaten and stripped but there was no evidence of sexual assault.
Miss Wanninkhof disappeared from her home on 9 October, 1999 and was found strangled and naked. She had not been sexually assaulted.
DNA has played an important role in the Spanish investigation.
Police now hope it will also help clear up several unsolved crimes back in Britain, according to BBC Home affairs correspondent Daniel Sandford.
A Scotland Yard spokeswoman told BBC News Online that police in the UK were still liaising with the Spanish authorities.
BBC correspondent Katya Adler, in Madrid, said there had been calls from the Spanish press and politicians for greater co-operation between police forces across the European Union on criminal records.
Bromwich was found guilty of choking five women unconscious with a piece of electrical cable or rope and then molesting them.
Sentencing him to 10 years in prison an Old Bailey judge called Bromwich a "Jekyll and Hyde monster" whose wicked personality was caused by sexual inadequacies.
Bromwich was granted parole in 1991 but sent back to prison eight weeks later for robbing a woman at knifepoint.
He was re-released in 1993.