The US manufacturer is under federal investigation for allegedly using illegal rosewood from Madagascar to make its guitars

Gibson Guitars is under invesigation for alleged use of smuggled wood. US federal agents raided a Gibson factory on Tuesday, claiming that they may have used illegal rosewood to make their guitars.

The US Fish and Wildlife Service seized wood, computers, files and guitars from Gibson's Massman Road manufacturing facility in Nashville, Tennessee. They are seeking evidence that Gibson shipped illegal rosewood from Madagascar via Germany.

Rosewood is expensive – more than double the cost of mahogany – and a crucial component in many guitars. Even at £3,000 per cubic metre, it can be found in acoustic guitar bodies and fingerboards. The troubled east African island of Madagascar, is a prime exporter of the hardwood. But due to corruption and environmental issues, Madagascan rosewood is a dubious proposition, and America's Lacey Act bars firms from bringing it into the US.

Gibson promised that they are "fully co-operating" with the federal investigation. "Gibson is a chain of custody certified buyers that purchases wood from legal suppliers who are to follow all standards," the company said. Gibson CEO Henry Juszkiewicz sits on the board of the Rainforest Alliance, which lobbies for sustainable forestry.