Los Angeles ? A multimillion dollar collection of Andy Warhol portraits of Muhammad Ali and other sports superstars was stolen from a Los Angeles home, police said Friday.

The 11 color screenprints were taken from businessman Richard Weisman’s home sometime between Sept. 2 and 3, said Detective Mark Sommer of the Los Angeles Police Department’s art theft detail.

Ten of the 40-inch-square portraits feature famous athletes of the 1970s, including golfer Jack Nicklaus, soccer star Pele and figure skater Dorothy Hamill. The other is of Weisman, likely a commissioned portrait.

A $1 million reward was being offered for information leading to the return of the artwork.

It wasn’t known exactly how much the prints were worth but Weisman tried to sell the collection in 2002 for $3 million.