Dano Sonnex should have been deemed a greater risk
The true extent of repeat offences by known violent criminals and sex offenders is being under-reported by the government, the BBC has learned.
A Panorama investigation into Mappa, a multi-agency public protection arrangement for released violent offenders, revealed that only those placed in the top two risk levels - two and three - are tracked in detail by police and probation services and their reoffend rates made public.
The majority of violent criminals in England and Wales, including sex offenders, are placed in the lowest tier - level one - and subjected to much less supervision.
These offenders are not included in annual reporting figures from the Ministry of Justice.
The latest figures are scheduled for release Monday.
Using freedom of information requests submitted to both probation and police services in England and Wales, Panorama has discovered that for the reporting period of 2008-9, there are at least 125 re-offences that will not make it into the official government figures.
Since they were first issued in 2001, the government's figures have consistently put the number of serious re-offences by the top two levels of criminals at around 70. These offences include murder, rape and serious sexual assaults.
The 2007-8 report stated that 79 offenders out of 12,800 being monitored at the high-risk levels had committed further serious crimes after their release.
Panorama queried the 42 police and 42 probation services in England and Wales. A combined total of 51 provided information for 29 areas on re-offending rates from 1 April 2008 to 31 March 2009 among level one offenders in their charge, of which there are more than 37,000.
Scotland has its own, similar monitoring scheme that began in 2007, as does Northern Ireland.
England and Wales justice minister Maria Eagle said the figures the government releases are intended to inform the public about the successes in monitoring the highest risk violent criminals and that plans to release information about everyone monitored by the Mappa scheme - more than 50,000 in total - have been delayed owing to concerns over accuracy.
"The figures are designed to put some information in the public domain about Mappa arrangements and how well they have succeeded over the year in reducing risk to the public and serious further offences is one way of judging that," she said of the scheme created by Jack Straw when he was home secretary.
'Dangerous human being'
Lapses in monitoring of released violent criminals led to Mr Straw's personal apology to the parents of two French students who were tortured and then murdered in June 2008 in New Cross, London, by Dano Sonnex and his accomplice, Nigel Farmer, during an alcohol and cocaine-fuelled attack.
Students Gabriel Ferez and Laurent Bonomo were tortured and killed
Sonnex had a violent past that included convictions for knife crimes and armed robbery.
Upon release from prison he was not assessed and therefore incorrectly placed on Mappa's lowest, level one tier of risk, meaning that he was only supervised by a single probation officer.
He should have been returned to jail following a breach of licence, but the warrant to arrest him was not executed before the murders.
In their first televised interview since their 23-year-old son Laurent's killer was sentenced in June, Guy and Lydie Bonomo told Panorama reporter Raphael Rowe that apologies are not enough.
Along with the family of the other victim, Gabriel Ferez, also 23, the Bonomos are planning to sue the Ministry of Justice for failing to ensure that Sonnex was properly tracked while on licence and returned to jail when he was caught with a stolen mobile phone.
"I discovered that Sonnex should have been in jail, that he was a very dangerous human being and probation officers probably knew that," Mme Bonomo said. "I heard there was a report about him saying that he was violent and dangerous and nobody took care of it, so that kind of action could have saved our children of course."
Guy Bonomo said the failings amount to far more than one person's human error.
"I can't accept this mistake, I can't accept he was in the bad moment in the wrong place, it is not a mistake it is horrible, I can't accept."
Harry Fletcher, chair of the National Association of Probation Officers, said lack of monitoring of known violent offenders placed on level one amounts to a lack of resources.
"Frankly there aren't enough police officers or probation officers to cover the cases that we've got."
There are about 250,000 people under supervision by probation services in the UK at any given time, of which about 30,000 are on licence.
On Mappa there are an average of 50,000 violent and sex offenders in England and Wales, many of whom are on licence, although some continue to be monitored even once their licence has expired.
Panorama: Freed to Offend Again, BBC One, Monday, 26 October at 2030GMT.