Police forces are monitoring social networks to harvest evidence on crimes, and use undercover officers to interact with people on Facebook, according to a senior police officer.
Police have gathered evidence on murder, theft, burglary, fraud, arson, and sex crimes through people not applying privacy settings on Facebook, ACPO e-crime prevention lead and deputy chief constable Stuart Hyde told the Counter Terror Expo on Thursday.
"If your Facebook is open and you allow people to come in — tough, we will do it," said Hyde.
Under the Regulation of Investigatory Powers Act (RIPA), the police can monitor open social networks without authorisation, said Hyde. To join a particular network, and then to start interacting with people, requires authorisation from a police authority or commissioner.
Hyde said that last year a group of people had tried to organise a rave in Cumbria through Facebook, but that they had been "pretty slapdash about who they invited" online. One of the people who was invited was a police officer, and when people turned up for the rave, the police were there.
Hyde said that Cumbria had not had to have RIPA authorisation to monitor the preparations for the rave.
"All we were doing was listening and watching," Hyde told ZDNet UK, who added that RIPA authorisations have been granted for undercover police to use Facebook.
"All aspects of RIPA have been used," said Hyde. "RIPA is there to protect people's privacy. We don't want a police state. Those engaging in monitoring were doing it properly."