Shomrim, the Jewish volunteer safety patrol, helped police arrest 153 suspects in the past year.
The strictly Orthodox group also located 38 vulnerable missing persons.
The figures, released by Shomrim’s Stamford Hill branch and covering its work in that area of north-east London, reveal that 21 of the arrests were for racially aggravated or racially motivated offences.
In the 12 months up to March 31, suspects were arrested in connection with a total of 185 offences, including theft (15 per cent of the total); burglary (12 per cent) and public order offences (19 per cent).