Another four registered sex offenders were 'missing' in the Thames Valley at the end of February.
The request revealed the force did not know the whereabouts of the offenders, whose crimes included rape and sexual assault, as of February 28.
Two of them are supposed to register in Berkshire and two in Buckinghamshire.
The request, which takes a month to process, revealed the total number of sex offenders in the Thames Valley on that date was 1,342, with 74 based in Windsor and Maidenhead.
It also showed police have received 182 applications for information under the Child Sex Offender Disclosure Scheme - known as Sarah's Law - since it came into play in October 2010.
But for cost reasons the force refused to provide details on how many of those applications have received responses.
The Advertiser made the information request after revealing in February that a convicted sex offender had been given a part in a Maidenhead production of the Sound of Music, which starred 14 children, even though police and the theatre company knew about his past.
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The victim of an assault in Cippenham was flown to hospital by air ambulance this afternoon.
A rapid response vehicle, an ambulance officer, an air ambulance and an ambulance crew were all called to an address in Earls Lane at 2.10pm.