UPDATE at 4:58 p.m., Friday, April 10: The FBI is launching an investigation. Read our latest here.

The San Bernardino County Sheriff's Department will launch an internal investigation after deputies were captured on video today beating a suspect who had led them on a vehicle and horse pursuit.

In a statement released tonight, Sheriff John McMahon said this:

The video surrounding this arrest is disturbing and I have ordered an internal investigation be conducted immediately. In addition, members of the Specialized Investigations Detail are responding to conduct the criminal investigation.

NBC Los Angeles' news-chopper camera captured some of the pursuit (video is below) and the subsequent confrontation, with its reporters saying they counted 13 deputies, 17 kicks, 37 punches, 13 strikes to the head and four blows with batons.

The guy also apparently was kneed.

The suspect had fallen off the horse and was on the ground with his arms outstretched when deputies pounced. NBC Los Angeles put it this way:

The man did not appear to move from his position lying on the ground for about 30 minutes. He did not receive medical attention while deputies stood around him during that time.

The sheriff's department says it all started at 12:12 p.m. today in the 25300 block of Zuni Road in unincorporated Apple Valley, when deputies went to a location to serve a search warrant related to an identity theft case.

The suspect, ID'd as 30-year-old local Francis Jared Pusok, allegedly took off in a vehicle, authorities said. The chase was on. Here's what the San Bernardino department says happened next:

Pusok abandoned the vehicle southwest of Bowen Ranch and fled on foot. Deputies were actively searching for Pusok on foot, using off-highway vehicles and helicopters. Within minutes, deputies received information that the suspect came into contact with a group of people near the Deep Creek Hot Springs and stole a horse. He fled on horseback on dirt trails, through very rugged, steep terrain, causing numerous injuries to the horse. 

Authorities had to deploy deputies via helicopter to arrest the suspect, officials said.

Pusok, they said, was thrown off the horse, and law officers descended on him with a Taser. The Taser didn't work as a result of “his loose clothing,” according to the sheriff's statement.

This all went down near Highway 173 and Arrowhead Lake Road, officials said.

Stay tuned for more.

ADDED at 6:38 p.m., Thursday, April 9: Authorities say the suspect was hospitalized “with unknown injuries.”

Additionally, three cops were injured. The San Bernardino department says:

Three deputies were injured during the search; two suffered dehydration and a third was injured when kicked by the horse. All three were transported to the hospital for treatment. 

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