A:
First,
it is not permissible
to threaten Muslims and compel them to stop Islamic activities practiced in the Masjids. Likewise, it is not permissible to search their houses and spy on them;
because Allah (Glorified be He) has prohibited spying and because this involves
cooperation in sin and transgression, which Allah (Exalted be He) has prohibited by His Saying:
...but do not help one another in sin and transgression.
Second,
if the salary these policemen receive is in return for doing the mentioned (Part No. 26; Page No. 6) deeds, it is an unlawful salary. It is payment for unlawful work and hence it is ill-gotten money, such as the money earned by a prostitute, a soothsayer, or from selling a dog.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.