Expert analysis of a Rover Thomas painting bought at auction four years ago has cast doubt on whether the indigenous master painted the work.

A preliminary report from Melbourne University’s Centre for Cultural Materials Conservation states that, in view of the evidence available, Grugrugi Owl “cannot be ascribed to the oeuvre of Rover Thomas”.

The report says: “If secure provenance exists then it should be presented and tested to determine the possible place of this work in the artist’s oeuvre.”

Grugrugi Owl was bought by a Sydney collector at a Lawson-Menzies auction in 2005 for $36,600. The collector sent the painting to the CCMC last year after reports in The Australian about problematic Thomas paintings in Lawson-Menzies auctions.

Although the report does not confirm nor deny authenticity, it draws attention to characteristics that may not be typical of Thomas’s work. These include: preparation and paint application, brush strokes, background colours and techniques, and the form of the owl featured in the work.