He was 67.
Eloy Leija, promotions manager for Gonzalez's label, Freddy Records, told the Brownsville Herald the musician was rushed to the hospital after "heart stopped and they brought him back to life." He later died at the hospital this morning.
Formed in the mid-1970s in Brownsville, Mazz helped expand the Tejano sound by incorporating synthesizers and elements from other Latin music styles. The group won the Grammy for Best Tejano Album in 2004 and four Latin Grammys for Best Tejano album during the early 2000s.
Mazz was a regular at San Antonio music events including the Tejano Conjunto Festival. He was scheduled to play local Tejano station KXTN's 30th-anniversary festival this summer.
KXTN will hold a candlelight vigil for Gonzalez tonight at Market Square.
