Police became aware Alice Gross murder suspect Arnis Zalkalns had previously been convicted for murdering his wife weeks after the Hanwell teenager went missing, an inquest heard.
DCI Andy Chalmers told jurors at London's Royal Courts of Justice on Monday (June 27) that police had contacted Latvian authorities about the west Ealing resident, who lived on Castlebar Road, as they investigated Alice's disappearance.
The 14-year-old was reported missing on August 28 2014 when she did not return from a walk, but her body was discovered in a bin bag in the River Brent on September 30.
Zalkalns, who went missing a week after Alice disappeared, was found hanged in woodland in Boston Manor Park on October 4.
But by then police had already begun looking at him as a potential murder suspect, DCI Chalmers told the inquest on Monday.
Police were told on September 19 that the 41-year-old had been convicted in 1997 of murdering his wife , having requested information on his previous convictions nine days earlier.
Despite his conviction, he was still allowed to travel to the UK to work as a builder, sometimes in Isleworth and sometimes in West Drayton.
An inquest into his death concluded that he likely killed Alice , possibly in a sexually-motivated attack as she looked similar to an ex-partner, and police confirmed they would have charged him with murder had he been caught.
Alice's mother Ros Hodgkiss addressed the jury on Monday morning in an emotional speech in which she said there were "unanswered questions" surrounding how the authorities allowed EU national Zalkalns to enter the UK and did not monitor him.
DCI Chalmers told the court at the new inquest, held to assess whether system failings contributed to Alice's death, it was possible that police pressure contributed to Zalkalns' suicide.
The inquest continues.