BBC investigators have spied on staff email accounts 140 times in past five years BBC Investigations Service staff have snooped on employees' accounts Probing alleged criminal activity including theft, bribery and harassment Also looked at alleged computer misuse and malicious communications The BBC has spied on the email accounts of its staff 140 times in the past five years, MailOnline can reveal today. Staff in an internal unit known as the BBC Investigations Service have snooped on employeesâ€™ accounts to probe alleged criminal activity including assault, fraud, theft, bribery and harassment. Requests for monitoring email accounts since 2009 have also been authorised for the investigation of computer misuse, information leaks, malicious communications and security incidents. Spying: Staff in the BBC Investigations Service have snooped on email accounts to probe alleged criminal activity including fraud, theft, bribery and harassment. BBC Television Centre in West London is pictured The BBC said probes â€˜generally involve members of BBC staff, our service partners or third parties whose activity adversely impacts on the BBC, whether this occurs on BBC premises or elsewhereâ€™. There have been 21 requests authorised in 2013 so far - which, if it fails to increase by more than two, is the lowest level in five years - below 30 in 2012, 40 in 2011, 24 in 2010 and 25 in 2009. The staff being monitored would have been unaware that their emails were being read, although the Corporation insisted employees are aware that monitoring can occur in â€˜exceptional circumstancesâ€™. The figures for 2012 were released in a Freedom of Information Act (FOI) request earlier this year, which revealed four monitoring requests were made for an apparent leak of information. It also showed that there were eight requests regarding computer misuse, six for fraud, one for harassment, one for bribery, two for malicious communication, two for theft and one police enquiry. Graphically shown: There have been 21 requests authorised in 2013 so far - which, if it fails to increase by more than two, is the lowest level in five years - below 30 in 2012, 40 in 2011, 24 in 2010 and 25 in 2009 The data for 2013 and the three years prior to 2012 was released to MailOnline following another FOI request that was responded to in 32 working days - 12 days over the legislationâ€™s 20-day limit. Monitoring of email accounts is invariably undertaken in relation to criminal or disciplinary investigations and staff are aware that monitoring can occur BBC spokesman Although the Corporation could not provide the breakdown for reasons behind requests, it said that the 40 in 2011 included complaints, security incidents, information leaks and even assault. Requests in 2009 and 2010 were for the likes of computer misuse, fraud and more information leaks. A BBC spokesman said: 'The BBC rarely monitors staff email accounts and only in exceptional circumstances where it is reasonable, necessary and represents a proportionate response.â€™ â€˜Monitoring of email accounts is invariably undertaken in relation to criminal or disciplinary investigations and staff are aware that monitoring can occur. Bribery (1) Computer misuse (8) Miscellaneous enquiry (4) Enquiry by Police (1) Fraud (6) Harassment (1) Information leak (4) Malicious communication (3) Theft (2) Assault Complaint Computer misuse Fraud Miscellaneous enquiry Security incident Information leak Theft Malicious communication