"He is the alleged mastermind of kidnappings and killings, mainly of members of other criminal organizations," according to the reward statement issued by the Attorney General's Office.
His work in organized crime predated La Familia's origins.
Mendez had been arrested nine years ago in the Michoacan city of Apatzingan on suspicion of killing gang members but was released, according to a news release from the federal Attorney General's Office. The office did not explain why he was released.
At the time, he headed a group of hit men that worked for the Gulf cartel in Michoacan and was protected by his own security team known as the "Twelve Apostles," according to the Attorney General's Office news release.
La Familia founder Moreno was killed in December during two days of shootouts between La Familia and federal police. After his death, La Familia split into warring factions, causing increased bloodshed in western Mexico.
The leader of a violent splinter group, known as the Knights Templar, remains at large.