Multiple sources tell us the person who Velasquez opened fire at near a school in San Jose, CA. earlier this week was the man who was accused of repeatedly sexually abusing Cain's close relative.

We're told the man lived at a home that hosts a daycare where Cain's young family member attended. Sources say the man allegedly molested Velasquez's relative there and was ultimately arrested and charged with one felony count of a lewd and lascivious act with a child under the age of 14 last week over the allegations.

The man, however, was granted a release from custody following an arraignment hearing last Friday despite strong opposition from the district attorney's office.

Our sources say the release infuriated Velasquez so much, he attempted to take justice into his own hands and shoot the man while he was in a car outside of a local school.

Velasquez was arrested and booked on a felony charge of attempted murder for the actions.

The former UFC fighter -- who has wins over Brock Lesnar and Junior dos Santos on his resume -- is due in court for a hearing on the matter later Wednesday.

Sources say he is expected to be formally charged by the DA's office prior to the court hearing.