At the age of 17, Vasquez was present at the slaying of Constable William Hardmount in a fight with Vasquez's cousin at a fandango. Vasquez denied any involvement. Fearing arrest, however, he became an outlaw. Vasquez would later claim his crimes were the result of discrimination by the norteamericanos and insist that he was a defender of the Mexican-American rights.
After his release, Vasquez made attempts to be law abiding, but eventually returned to crime. He was captured after a robbery in 1867 and sent to prison again for a short time.
Vasquez moved to Southern California, where he was less well known. With his two most trusted men, he rode over Tejon Pass, through the Antelope Valley, and rested at Jim Heffner's ranch at Elizabeth Lake. Vasquez' brother, Francisco, lived nearby. After resting, Vasquez rode on to Littlerock Creek, which would become his first Southern California hideout.
Governor Booth was now authorized by the California state legislature to spend up to $15,000 to bring Vasquez to justice. Posses were formed in Santa Clara, Monterey, San Joaquin, Fresno, and Tulare Counties. In January 1874, Booth offered $3,000 for Vasquez's capture alive, and $2,000 if he was brought back dead. The rewards were increased in February to $8,000 and $6,000. Alameda County Sheriff Harry Morse was assigned specifically to track Vasquez down.
Heading towards Bakersfield, Vasqez and his gang rode south to the rock promontory now known as "Robbers Roost" after him. From there, the gang could rob coaches from the silver mines near Owens Lake. However, pickings were poor. Vasquez also shot and wounded a man who didn't obey his orders. Because of this, the stages would add a shotgun rider beside the driver.
The gang moved to Elizabeth Lake and Soledad Canyon, robbing a stage of $300, stealing six horses and a wagon near present day Acton, and robbing lone travelers. Vasquez was believed to be hiding out at Vasquez Rocks. For the next two months, he escaped attention. However, he then made an error that led to his capture.
Vasquez took up residence in the Hollywood Hills at "Greek George's" ranch, located on the San Fernando Valley side of the Cahuengas Mountains. Greek George was a former camel driver for General Beale in the Army Camel Corps. Allegedly, Vasquez seduced and made pregnant his own niece. Either the girl's family or Greek George's wife's family betrayed Vasquez to Los Angeles Sheriff William Roland. Roland led a posse to the ranch and captured Vasquez on May 13, 1874.
Vasquez remained in the Los Angeles County jail for nine days. He had numerous requests for interviews many newspaper reporters, but agreed to see only three: two from the San Francisco Chronicle and one from the Los Angeles Star. He told them that his aim was to return California to Mexican rule. He insisted he was an honorable man and had never killed anyone.
In late May, Vasquez was moved by steamship to San Francisco. He would eventually stand trial in San Jose. Vasquez quickly became a celebrity among many of his fellow Hispanic Californians. He admitted he was an outlaw, but again denied he had ever killed anyone. A note written by Clovidio Chavez, one of his gang members, was dropped into a Wells Fargo box. Chavez wrote that he, not Vasquez, had shot the men at Tres Pinos. Nevertheless, in January 1875 Vasquez was sentenced to hang for murder. His trial had taken four days and the jury deliberated for two hours before finally finding him guilty of two counts of murder in the Tres Pinos robbery.
Visitors still flocked to Vasquez's jail cell, many of them women. He signed autographs and posed for photographs. Vasquez sold the photos from the window of his cell and used the money to pay for his legal defense. After his conviction, he appealed for clemency. It was denied by Governor Romualdo Pacheco.