MEXICO CITY (Reuters) - Mexican federal police have captured suspected murderer, rapist and drug gang member Joe Luis Saenz, one of the 10 most wanted fugitives on the FBI's list, the government said on Friday.

Saenz, a U.S. citizen, was arrested in the city of Guadalajara in western Mexico on Thursday following an investigation by the federal police in conjunction with the FBI, the government said in a statement.

Saenz will be returned from Mexico to Los Angeles this weekend under FBI escort, said a statement from the FBI.

According to the FBI, Saenz is suspected of shooting and killing two rival gang members in Los Angeles in July 1998.

Less than two weeks later, Saenz allegedly kidnapped, raped, and murdered his estranged girlfriend. Saenz also is believed to have murdered another man in October 2008 in Los Angeles County.

FBI records suggest Saenz is 36 or 37, and the bureau offered up to $100,000 for information leading to his arrest.

Born in Los Angeles, Saenz was known to travel between the United States and Mexico, and was believed to be working for a Mexican drug cartel, the FBI said. He had a number of aliases including Zapp, Peanut Joe Smiley and Honeycutt, it said.

(Writing by Dave Graham; Editing by Bill Trott)