Deputy sheriffs in southern California were under investigation Friday after a TV news helicopter caught them on video kicking and beating a suspect who was fleeing on horseback.
Francis Jared Pusok, 30, a white male with a criminal record, was kicked 13 times, punched 37 times and struck four times with batons, according to KNBC television in Los Angeles.
"I'm disturbed by what I see in the video," San Bernardino County sheriff John McMahon told the station, whose chopper hovered over the scene.
He ordered an internal investigation into the incident, which occurred in desert scrub in Apple Valley, 80 miles (130 kilometers) from Los Angeles.
It came five days after a white police officer in the South Carolina city of North Charleston was caught on video gunning down a fleeing African American suspect.
The officer, Michael Slager, has since been charged with the murder of Walter Scott, 50, and fired from the force, in the latest fatal confrontation in the United States between white police officers and unarmed black suspects.
Pusok was being served a warrant related to an identity theft investigation when he first fled on foot, then stole a horse, the San Bernardino County Sheriff's Department said in a statement.
From the KNBC video, it appeared Pusok was zapped with a Taser when he fell off the horse, after which up to 11 deputies began striking him.
He remained on the ground for 45 minutes, getting no medical attention before he was taken to hospital, the television station reported.
The sheriff's department acknowledged that "use of force occurred" after the Taser proved ineffective due to "loose clothing" that Pusok was wearing.
Three deputies also got medical treatment -- two for dehydration and a third who got kicked by the horse, which itself sustained "numerous injuries."
Court records show Pusok had prior convictions for resisting arrest, animal cruelty, disturbing the peace, attempted robbery and failure to prove evidence of financial responsibility, KNBC said.
Pusok made local news headlines in November 2013 when he was arrested at his Apple Valley home after allegedly threatening his girlfriend and shooting a dog.
The San Bernardino County Sheriff's Department is itself facing several lawsuits over its use of Taser guns, including one filed in March by the American Civil Liberties Union (ACLU).
"Too often the department has failed to address questions" about its use of force, the organization's southern California chapter said in a statement.
Last month, officers from the Los Angeles Police Department were seen fatally shooting a homeless man in the city's notorious Skid Row district, in a video that soon went viral.
Police said the victim in that case had tried to get hold of an officer's firearm.