Nuno and Luis Ramos were part of a gang who raided a businessman's house, tortured him and left him to suffocate.
When they were jailed for manslaughter, the judge at their trial said they should be sent back to their homeland, Portugal, at the end of their sentences. The then-home secretary agreed.
Yet after a five-year legal battle, immigration judges have overturned the deportation orders and ruled that the brothers can stay in the country.
In the case of Nuno Ramos, 26, the judge who made the decision said it was based partly on his right to enjoy a family life in Britain with his girlfriend, who his does not live with; their baby boy; and Luis Ramos, 24, his killer brother
The cases are thought to have cost taxpayers tens of thousands of pounds in Legal Aid. It is one of only a handful of times that convicted killers have been allowed to stay in Britain on human rights grounds.
It has echoes of the high-profile case of Learco Chindamo, the Italian-born gang member who murdered Philip Lawrence, the headteacher, outside his north London school, but who later overturned a Home Office bid to remove him from the UK.
The decision to allow the Ramos brothers to stay in the UK will highlight concerns over the way criminals can claim human rights to avoid deportation - in particular Article 8 of the European Convention of Human Rights, which guarantees the right to enjoy a "private and family life".
Nuno and Luis Ramos came to Britain from Portugal in 1998, aged 12 and 10. In July 2003 they were in a gang of eight youths, including three girls, who burst into the northwest London home of Joao DaCosta Mitendele, 47, to rob him.
Nuno Ramos had recruited his friends to carry out the raid after being encouraged to do so by his then-girlfriend, who knew the victim, the brothers' Old Bailey trial heard.
Mr Mitendele was clubbed with a baseball bat, stabbed in the legs, bound by his hands and feet, and had a black cloth bag taped over his face. The gang fled with cash, jewellery and a camcorder, leaving their victim lying face down in his hallway. It took him up to 45 minutes to die.
At the trial, Nuno Ramos admitted manslaughter and conspiracy to rob, while Luis denied both offences but was convicted by a jury.
Handing down sentences, Judge David Paget QC described the crime as "wicked and callous" and told Luis Ramos: "You must have been aware as you left that he was struggling for breath, or before you left, and you must have stepped over his body in order to leave."
Nuno Ramos was sentenced to nine years, Luis Ramos to seven. The Home Office served orders to deport both men when their sentences finished - even though, as European Union nationals, they can only be deported if there are "serious grounds of public policy or public security" for doing so.
Luis Ramos, the first to be freed, appealed against deportation and eventually won his fight. However, his hearings took place without publicity, and his story has only emerged now with the publication of a judgment in his older brother's case.
Nuno Ramos launched an appeal from his prison cell in 2008 against his deportation order, which would have banned him from returning to Britain for 10 years.
Despite his involvement in the killing, and two drugs offences committed after his release, immigration judges ruled that he does not represent a threat to the public. They said that this, combined with his "family life" right, meant he could stay in Britain.