(CNN) -- Authorities have arrested one of the FBI's 10 Most Wanted Fugitives in Mexico, the FBI said Friday.
Jose "Joe" Luis Saenz, who was wanted in multiple slayings in Los Angeles, was captured late Thursday. Exactly where is not known.
Bill Lewis, assistant director in charge of the FBI's Los Angeles field office, thanked the various groups involved in Saenz's arrest, including the Mexican federal police, the Mexican National Institute of Immigration, the Mexican attorney general and the FBI's legal attache in Mexico City and its sub-office in Guadalajara, Mexico.
Saenz is expected to return to Los Angeles from Mexico this weekend under FBI escort.
The FBI accuses Saenz of killing four people, two rival gang members and his girlfriend in 1998, and a fourth victim 10 years later. He is also accused of kidnapping and raping his girlfriend, who is the mother of his child.
The FBI was offering a reward of up to $100,000 for information that led directly to his arrest.
Saenz was added to the FBI's list of 10 Most Wanted Fugitives in October 2009.
"This individual, Jose Saenz, will be brought to justice," Los Angeles County Sheriff Lee Baca said then. "We will find him and prosecute him to the full extent, under the law. Make no mistake about it."