Police raided a flat in the Market Place, Devizes, and arrested two people last Friday.
They executed a warrant after being told of suspicious activity at the flat, above Greggs, but failed to find significant quantities of illegal drugs.
Inspector Matt Arm-strong, of Devizes police, said: “The warrant was issued under the Misuse of Drugs Act. My officers found a small quantity of cannabis.
“One person has been cautioned for the possession of cannabis and one for permitting the use of premises for the smoking of cannabis.
“This shows the public that we do act on information supplied by them.”