Colombia ? When a grand piano played an off-key note, drug police in this Caribbean port opened it up and found some 560 pounds of cocaine stuffed inside.

The piano was part of a shipment of household items originating in the capital of Bogota and destined for Panama, police said in a statement Monday.

Authorities were investigating, but had made no arrests. The drugs’ value was estimated at $5 million.

Agents in Cartagena noticed the piano was suspiciously heavy and decided to tap some keys, only to find the sound quality seemed strange, the statement said. The cocaine was discovered packed into various recesses of the instrument.