Four men are due to appear in court in relation to historic abuse at a school in Stowmarket.
The investigation relates to alleged offences carried out between 1975 and 1999 at Oakwood School and officers have spoken with more than 100 people since it began in 2011.
A 58-year-old man from Southampton, a 69-year-old man from Gislingham, a 59-year-old man from Northampton and a 65-year-old man from Lancaster have been reported for summons to court.
They are due to appear at Bury St Edmunds Magistrates' Court in connection with child cruelty and assault offences.
Eric De Smith, 74, of Danes Close, Stowmarket, was previously charged with gross indecency and indecent assault.