Heroin with an estimated street value of at least £32,000 has been seized from properties in Burnley.
Lancashire Police officers raided addresses in Claughton, Cleaver and Colbran streets on Wednesday.
They also found a stun gun, baseball bats and several thousands of pounds in cash.
Three men aged 23, 27 and 30, and a 28-year-old woman, have been arrested on suspicion of conspiracy to supply class A drugs and remain in custody.
Det Sgt Martin Kennedy, of Lancashire police, said: "This was a significant seizure of what is believed to be class A drugs and should demonstrate our commitment to tackling drug related crime in Burnley."