The Intelligence and Security Committee’s long-awaited report yesterday labelled an unnamed internet company, widely reported to be Facebook, a “safe haven for terrorists” because it did not flag up the online exchange between Michael Adebowale and a foreign jihadist, which took place five months before Fusilier Rigby’s murder.
The parliamentary watchdog’s chair Sir Malcolm Rifkind stated that the web firm could have made a difference by raising the conversation, and said there was “a significant possibility that MI5 would have been able to prevent the attack” as Adebowale would have become “a top priority”.
Fusilier Rigby’s sister Sara told the Sun newspaper: “Facebook have my brother’s blood on their hands.
“I hold them partly responsible for Lee’s murder.”
Fusilier Rigby’s stepfather Ian said: “Facebook failed us all when they failed to alert our authorities.”
A Facebook spokesman said: “Like everyone else, we were horrified by the vicious murder of Fusilier Lee Rigby.
“We don’t comment on individual cases but Facebook’s policies are clear, we do not allow terrorist content on the site and take steps to prevent people from using our service for these purposes.”
Fusilier Rigby’s family later told Good Morning Britain the report had left them with “a lot of questions”.
Mr Rigby said internet companies have a duty of care towards their customers and should pass information on when necessary.
Asked if he would like to put his questions, including why there was a delay in information being passed to intelligence agencies, to David Cameron he said: “Yes, he’s the only one that has the full report and he’s probably the only one that could get the answers that we want.”
A number of online accounts owned by Adebowale were automatically disabled due to association with terrorists and terrorism - but the unnamed web firm was unaware as it does not manually review such decisions, and it did not notify law enforcement agencies.
Adebowale was in contact with an extremist now known to have links to al Qaida in the Arabian Peninsula (Aqap) in late 2012, the report said, however this was not revealed until an unidentified third party notified GCHQ after the attack.
The group of MPs said in their report that it was “highly unlikely” the intelligence agencies would have seen the discussion, which came to light only after the barbaric murder near Woolwich barracks on May 22 last year, without the company’s help.
The committee also concluded that the three intelligence agencies - MI5, MI6 and GCHQ - could not have prevented the murder of Fusilier Rigby despite a litany of errors and missed opportunities in seven previous operations featuring Adebowale and Adebolajo.
Facebook is mentioned in the ISC report - but only as one of a number of communication service providers in the US from which UK agencies face “considerable difficulty” in accessing the content of communications. Apple, Google, Microsoft, Twitter and Yahoo are also named.
Yesterday Mr Cameron, who announced £130 million in funding to improve the agencies’ capability to combat “self-starting” terrorists, attacked internet firms for failing to help tackle the threat.
He said: “Terrorists are using the internet to communicate with each other and we must not accept that these communications are beyond the reach of the authorities or the internet companies themselves.
“Their networks are being used to plot murder and mayhem. It is their social responsibility to act on this and we expect them to live up to that responsibility.”
Fusilier Rigby’s uncle Raymond Dutton said he does not believe his nephew’s brutal murder was preventable.
“I honestly don’t believe it could have been averted but perhaps the learning from the report is what we can do with the information we’ve gleaned from this sad murder of my nephew.”
Muslim converts Michael Adebolajo and Adebowale ran down Fusilier Rigby, who was dressed in a Help For Heroes hoodie, in a Vauxhall Tigra near Woolwich Barracks, in south east London, before savagely attacking the defenceless soldier as he lay in the road.
Human rights campaigners and civil liberties groups have raised concerns that the committee has “spun the facts” to shift blame on net firms and away from the intelligence agencies, while Adebolajo’s brother said the report is a “distraction” from the UK’s “continuing aggression against the faith and people of Islam”.