CNN quoted authorities as saying Monday Gamez was killed, along with two men, Saturday during a clash between criminals and military troops in Mocorito.
The state attorney general told the American television news network Gamez is suspected of having ties to criminals, but offered no details regarding that alleged connection.
"We are dismayed by the news -- a beautiful young person, happy, and with a big future ahead of her," organizers of the Our Sinaloa Beauty 2012 beauty pageant, of which Gamiz was also a contestant, said in a statement to CNN Monday. "Rest in peace, Susy."
CNN did not specify her fatal injuries or say if any arrests were made in the triple homicide.