Thieves have stolen musical instruments worth £15,000 from the rehearsal room of the Vale of Glamorgan silver band.
South Wales Police said the raiders must have used a vehicle to grab the instruments from Barry Athletic Club, Barry Island, Vale of Glamorgan.
They struck between 1000 BST on Monday 31 January and 1800 BST on Tuesday.
Det Con Lee Davies said: "This is a particularly unpleasant crime. They have worked hard to build up their collection of musical instruments."
He added: "The band is made up of volunteers who perform at special events throughout the borough.
"The theft took place some time during the week between rehearsals and the amount of instruments stolen would have required a vehicle to take them away."
He appealed for people living in Paget Road on Barry Island who may have seen or heard a vehicle, possibly in the early hours of the morning, to contact them
He said: "This is a very unusual crime and we will do all we can to bring those responsible to justice."