A reward of nearly 700,000 euros is being offered for information leading to the return of a multi-million dollar collection of Andy Warhol silk screen portraits.Featuring sporting superstars of the 1970s, the ten works were stolen from the Beverley Hills home of a Los Angeles businessman. Police think they will be difficult to sell on. ‘‘Artworks of this significance are very hard to move and so I believe, just based on past experience, these will surface. At some point they will show up. It is just a question of whether it is sooner or later,’‘ said Detective Don Hyrcyk from Los Angeles Police Department. Portraits of boxing legend Muhammad Ali, football star Pele, figure skater Dorothy Hamill, ice hockey’s Rod Gilbert and trial of the century defendant OJ Simpson were among the pictures taken. An iconic figure in the pop art movement, Warhol died in 1987.