The jury also found Vicente Jasso guilty of the special circumstances of kidnapping and robbery.
He now faces life in prison without the possibility of parole.
In 2023, Melanie Camacho was reported missing. She was last seen leaving her job at Auto Zone in Madera.
Friends and co-workers said she was going to see Jasso who she broke up with after dating him for three months.
Investigators eventually found Camacho dead in a Madera County field.
A second man, Jose Lopez Hernandez, was also arrested and he later pleaded guilty to a felony charge of accessory after the fact.
He was sentenced to three years in prison in February 2025 and has since been released.
Sentencing for Jasso is set for April 16.