A Mexican business tycoon was charged Thursday with illegally funneling more than $500,000 to support San Diego politicians in a widening campaign finance scandal.

Jose Susmo Azano, 48, pleaded not guilty in federal court to being a foreign national who provided campaign contributions.

Prosecutors contend that Azano and several other people were involved in illegal donations to independent committees backing four candidates for mayor and Congress in 2012 and 2013.

Azano, who was arrested Wednesday, heads Grupo Azano SA, a conglomerate of construction and security companies based in Guadalajara, Mexico. He sells surveillance equipment to governments around the world.

San Diego, the nation's eighth-largest city, is home to many wealthy Mexicans who cross daily from Tijuana. Others have second homes in the pricey seashore neighborhoods of Coronado or La Jolla.

Last month, the FBI raided two Coronado homes owned by Azano's family.

Azano's wife and children are U.S. citizens. He was in the country on a short-term visitor visa that the State Department will revoke, likely within days, Assistant U.S. Attorney Timothy Perry said.

Azano's bail was set at $5 million. He was ordered confined to a San Diego-area home, to wear a GPS device and to surrender his travel documents.

Charges filed last month didn't offer a motive for the alleged donations. But Perry said at a previous bail hearing for one of the defendants that the businessman wanted to develop property in San Diego and turn its downtown waterfront into "Miami West."

The complaints filed last month describe a $100,000 donation to support one mayoral candidate, $190,000 to help another mayoral candidate and $30,000 for a candidate for federal office.

The complaints also mention an unidentified "straw donor" who allegedly took a $380,000 check from the businessman to funnel the donations.

Previously charged in the case were Ernesto Encinas, who provided security to Azano; Ravneet Singh and his Washington-based campaign services firm ElectionMall Inc., and Marco Polo Cortes, a San Diego lobbyist.