Claims two men caught vandalising cars on CCTV in Norwich were not taken to court because of cost are being probed.
Norwich Police are to query a letter sent to a criminal damage victim in which reasons were given why the men were only cautioned.
No further action was taken because they were "unemployed foreign nationals with no income", the letter claims.
Norwich Police said the cautions had nothing to do with ethnicity or income.
'Pursue compensation'
A spokesman said they would be asking for a copy of the letter which appears to have been sent by an officer from the force to one of the victims.
The two men, aged 19 and 29, were arrested after they were seen on CCTV damaging two cars in Magdalen Street, Norwich.
In interview with police the men later admitted to eight other offences in the street or surrounding area involving other vehicles.
Norfolk Police said: "In this case the caution amounted to an admission of guilt for all 10 offences as opposed to the two that we had secured some evidence on.
"This caution, whilst not a conviction, is added to their police record and can be cited in court should they re-offend.
"The victims, if they wish to do so, can pursue compensation through the civil courts."
The decision to opt for a caution can also be influenced by such factors as the seriousness of the offence, previous convictions and good character.