The gambling tycoon Jorge Hank Rhon, an eccentric former mayor of Tijuana who collects exotic animals, has been arrested after the army found a large weapons cache in his home.
The millionaire businessman, who owns a successful chain of casinos, a football team and racetrack, was arrested during a raid in a wealthy Tijuana neighbourhood, the army and federal prosecutors said.
Soldiers launched the sweep after receiving an anonymous tip, surprising Mr Hank Rhon and 10 other people with a stash of 40 rifles, 48 pistols and a gas grenade, the statement said.
The 55-year-old Mr Hank Rhon and his fellow suspects were held at the local attorney general's office before being transferred to an air force base in Tijuana under army and police guard.
Mr Hank Rhon belongs to a prominent political family linked to the opposition Institutional Revolutionary Party, or PRI. His arrest could become a flashpoint ahead of hotly contested gubernatorial elections in the State of Mexico next month.
A colourful character who often sports a red crocodile-skin vest, Mr Hank Rhon was mayor of Tijuana, a busy drug trafficking corridor city across from San Diego, California, from 2004 to 2007. He once ran for governor of Baja California state but lost.