LOS ANGELES — A group of San Bernardino sheriff’s deputies were captured on videotape Thursday repeatedly pummeling and kicking a suspect after he fell off his horse at the end of a bizarre chase through rough California desert.

The county sheriff, John McMahon, called the video “disturbing” and said he had ordered an investigation into the episode, in which deputies chased the man by foot, helicopter and off-road vehicles. They shot him with a Taser when he fell off the horse. Video taken from a television station’s helicopter shows about a dozen deputies swarming the man as he sprawled on the ground. The video shows a blur of kicks and pounding fists that appeared to continue after the suspect’s hands were tied behind his back, and lasted close to two minutes.

The suspect was identified as Francis Pusok, 30, of Apple Valley, a community on the edge of the Mojave Desert about 100 miles north of Los Angeles. He was taken to a hospital with undisclosed injuries, according to the sheriff’s office.

There were no other immediate details about the suspect. The sheriff’s office said the encounter began when deputies went to his home and sought to serve him with a search warrant on suspicion of identity theft. They said three deputies were hurt during the capture of Mr. Pusok; one was kicked by a horse and two suffered dehydration.