Three men and one woman are in custody on suspicion of producing drugs in Rotherham.
South Yorkshire Police has just revealed that a man arrested this morning following a raid of a property in Broom Valley Road, Broom, was the fourth to be taken into custody.
Two other men and a woman were arrested last night, the force has revealed.
All four are being held on suspicion of drug production.
Chemicals found at the address in Broom are being analysed, with emergency services on stand-by as a precaution.
Broom Valley Road is closed as a precaution.