A neighbor said he turned on his camera after he saw Anthony Sanchez repeatedly hit the boy while the two were playing catch.
The neighbor, Oscar Lopez, secretly shot the video Wednesday from inside his house. It shows the boy dropping the baseball, then Sanchez hitting him with the belt before Lopez starts shouting to stop. Lopez said he posted the video on Facebook and YouTube then gave it to authorities.
Sanchez was arrested on Friday, but he hasn't appeared in court. He is a district director for Imperial County's Board of Irrigation. He also reportedly coaches t-ball and soccer.
The 34-year-old was held on $100,000 bail. Sanchez's attorney acknowledged the video is disturbing, but urged people to wait until details were revealed before reaching conclusions.
The Associated Press contributed to this report.