LONDON Detectives believe that such was the horrific nature of the Sally Anne Bowman murder that Mark Dixie may well have killed before, possibly in Australia.
Dixie, 37, had spent about six years there during the 1990s, many of those as an illegal overstayer, and had already been caught up in one of the country's most infamous murder cases.
After arriving in 1993, he lived in the Sydney beach suburb of Manly and later in Perth, Western Australia.
He also travelled through Queensland, Victoria, and South Australia. Detectives investigated him in connection with the infamous "Claremont" killings, which occurred while he was living in Perth.
Jane Rimmer, 23, Ciara Glennon, 27, and Sarah Spiers, 18, were abducted and killed after a night out in the upmarket Perth suburb of Claremont between 1996 and 1998.
Dixie was cleared after a failed DNA test and giving a provable alibi.
Last year, British detectives travelled to Australia to investigate suspicions that Dixie had attacked a female Thai student in Perth in 1998.
In that incident he was suspected of raping and stabbing the student, now 30, in an almost identical attack to the Bowman murder.
No one was ever charged with that attack but the woman travelled to London and gave evidence at the Bowman trial.
In 1999, under the alias Shane Mark Turner -- one of several he has used -- he was fined 750 Australian dollars for indecent exposure.
In that incident, in Busselton, a small town south of Perth, he drove past a woman out jogging, hid in some bushes and jumped out in front of her, exposing himself.
He fled but was caught just hours later.
He was also convicted of minor drug offences.
British officials believe Dixie has another conviction in Australia but say they have been unable to confirm the details with Australian police.
The Australian authorities, they say, did not inform anyone about his convictions when he was deported later in 1999.
"What the Australians did (by) deporting him back to the United Kingdom was the easy option to get him out of the country," said one senior Scotland Yard detective.
He said there was a possibility that, had authorities known about his previous attacks in Australia, Sally Anne Bowman might not have died.
Scotland Yard detectives say that such was the graphic nature of the Bowman killing that Dixie must have "graduated" to it in crimes elsewhere.
"We believe this is not the first murder he has done," one senior source said. "There are probably going to be more offences. I am convinced he has done something in Australia."
He said any unsolved murders that had been particularly gruesome and sexually motivated should be investigated -- especially if any DNA was left at the scene.
Another detective told Reuters: "Due to the nature of her murder it showed us that he has had some practice before."
(Editing by Stephen Addison)