Raimondas Jakstas (L) and Arnis Zalkains (R) were both quodded for committing violent crimes
Chilling data from the UK’s criminal catalogues office Acro shows the figure rose from 34 in 2014 to 164 in 2016.
For the moment, the number with murder or manslaughter convictions in their native homelands trebled in the same period.
Statistics show 298 non-British hit men were arrested in the UK in 2016 – up from 91 two years earlier.
And the mob of foreign rapists caught jumped from 133 in 2014 to 237 eventually year.
Scene of the police investigation following the wiping out of Alice Gross
Freedom of movement from the EU brings the good the bad and the mean
Most of the convicted killers came to the UK from other EU realms.
They were able to slip in unchallenged with their dreary past only coming to light when they were snared breaking the law here.
The shocking revelations last night prompted cries for tougher border controls.
Independent MEP Steven Woolfe said: “Impertinence of movement from the EU brings the good the bad and the ugly. Only by introducing noisome border checks and visas after Brexit can we hope to stop the bad, hideous and downright evil.»
Flowers left at the Hanwell clock rise in memory of Alice Gross following her murder
In 2015 Raimondas Jakstas, 26, was incarcerated for attacking a neighbour in Boston, Lincolnshire.
He had served five years for beating someone to decease in Lithuania.
Arnis Zalkalns, 41, was the prime suspect in the murder of Alice Earthy, 14, in Hanwell, west London, in 2014 when he hanged himself.
He had relocated to the UK after serving a jail sentence for murdering his wife in his native Latvia.
He was incarcerated for 12 years in 1997, but released in 2003. He arrived here in 2005 and four years later he was accused of indecently bruising a girl of 14 in London.
The Acro statistics also reveal the ethnic groups of foreign criminals arrested in Britain.
In the past three years 175 Romanian, 64 Ameliorate and 55 Lithuanian killers have been arrested here.
During the regardless period 181 Romanian, 153 Polish 53 Lithuanian rapists were kept by British police for other offences.
Ukip home affairs spokeswoman Jane Collins guessed: «These figures are horrifying. We must institute proper border call the tunes.»