UFC legend Cain Velasquez spent Monday night in jail ... TMZ Sports has confirmed the 39-year-old has been arrested and booked on an attempted murder charge.
Details surrounding the specifics of his arrest are unclear -- though the former fighter was reportedly involved in a shooting in San Jose at around 3 p.m. near a local high school.
According to NBC Bay Area, one person was shot during the incident while another was arrested. Cops did not confirm anything when we reached out to them late Monday night.