A California man was arrested for murdering his girlfriend’s 3-year-old son after confessing to stomping on the toddler’s head, authorities said.

Santos Rodriguez, 24, of Desert Hot Springs, allegedly told cops he killed the child on Saturday in a fit of rage, the San Bernardino Police Department said.

When the toddler was taken to a local hospital with severe head trauma, Rodriguez allegedly told medical personnel and investigators that the boy had fallen off a razor scooter and struck his head on the pavement, authorities said.

But during an “extensive investigation,” Rodriguez allegedly admitted to losing his temper and repeatedly stomping the little boy’s head on the ground, cops said.

Rodriguez was taken to the San Bernardino West Valley Detention Center, where he is being held without bail.