Three men who admitted stealing £200,000 of computer equipment from schools across Suffolk and Essex have been jailed.
Fifty-six primary schools and colleges were targeted following detailed research by the gang into the location of IT departments and security arrangements.
Among those raided were Kersey Primary School, Monks Eleigh Primary School and Bulmer Primary School.
Ipswich Crown Court heard on Friday that others were believed to have been involved in the night-time raids, but they have never been caught.
Appearing in court were Christopher Kerr, 25, of Halstead Road, Frinton; Liam Cook, 26, of Bushell Way, Frinton; and Francis Wilding, 22, of Broadway, Jaywick. The trio all pleaded guilty to conspiracy to commit burglary between August 2012 and May 2013.
Kerr admitted involvement in 16 raids, Cook in five and Wilding in 28. Prosecutor Martin Mulgrew described the three as “professional burglars”. In total, they raided 31 schools in Suffolk and 25 in Essex.
Despite more than 300 computers being taken, none were recovered.
The gang was caught after Wilding left traces of blood at one location which allowed police to trace him and seize his mobile phone which revealed details of calls to Cook and Kerr.
Mr Mulgrew said: “It is undoubtedly the case that hours of work prepared by teachers and pupils on the computers has been lost.”
From Kersey, the gang stole 28 laptops, from Monks Eleigh 14 laptops and a further 10 from Bulmer.
The court heard that, as the gang forced open windows at the schools, they caused damage amounting to more than £37,000.
The arrest of the three men came during Operation Justine, set up by Suffolk and Essex Police to tackle the problem of school burglaries.
Defence solicitors told the court that Wilding had acted out of character and had expressed remorse, while Kerr had been trying to make ends meet and was ashamed of what he had done.
Cook admitted helping move computers from the schools but said some of the internet searches he carried out were innocently on behalf of his young children.
Wilding and Kerr were each jailed for 64 months and Cook for 40 months.