This image provided by the Los Angeles Police Department on Friday Sept. 11, AP – This image provided by the Los Angeles Police Department on Friday Sept. 11, 2009 shows a reward poster …

LOS ANGELES – A unique series of Andy Warhol pieces — portraits of Muhammad Ali, Jack Nicklaus, Pele, Dorothy Hamill and other athletic superstars — has been stolen from a collector's home.

Los Angeles police said Friday the collection of 10 silk screen paintings of famous athletes of the 1970s was taken from the home of businessman Richard Weisman sometime between Sept. 2 and 3.

Weisman commissioned the iconic pop artist in 1977 to create the portraits, said Brenda Klippel, the director of Martin Lawrence Galleries in Los Angeles, which has a large collection of Warhols.

A commissioned portrait of Weisman was also stolen, said Detective Mark Sommer of the Los Angeles Police Department's art theft detail. A $1 million reward was offered for information leading to the return of the paintings.

"This was a very clean crime," Sommer said. "(The home) wasn't ransacked."

Art recovery expert Robert Wittman, a former investigator for the FBI's national art crime team, says most rewards are offered for about 10 percent of a stolen collection's value.

"A million dollars is nothing to sneeze at. That's a hefty reward for a collection," Wittman said.

The art was on display in Weisman's dining room and his house was locked up. It wasn't clear exactly when the paintings were taken or how the thieves got into the home.

The theft was discovered by the family's longtime nanny who arrived at the home to find the large prints missing from the walls. She immediately went to a neighbor's to call police, Sommer said.

It wasn't known exactly how much the prints were worth.

"The theft of Warhol's 'Athlete Series' represents a profoundly personal loss to me and my family," Weisman said in a statement.

Weisman, who published a book about his art collection called, "From Picasso to Pop," declined to comment further. The other valuable art in his home was untouched.

A neighbor saw a maroon van in the driveway of Weisman's home around the time of the robbery, Sommer said.

Warhol became internationally famous in the 1960s for his iconic image of a Campbell's soup can, his avant-garde films and his parties that mixed celebrities, artists, intellectuals and other beautiful people at his New York studio called "The Factory."

"Warhol was always a portraitist and fascinated with anyone of fame or fortune, anyone in the public eye," Klippel said. "If Weisman was in his circle and had the money, he could commission what he wanted."

Wittman said about 95 percent of stolen art, especially well known pieces, are recovered.

"The real art in an art theft is not the stealing but the selling," he said. "People know what they are. You can't sell it to the industry, it's not going back to the market and you also can't sell it at auction."