Huh. That taser didn't look ineffective to me:

Deputies appeared to use Tasers to stun a man and then beat him after the pursuit in San Bernardino County Thursday afternoon.

Aerial footage captured by NewsChopper4 showed the man falling off the horse, and then being stunned with a Taser by a sheriff's deputy.

The man then appeared to fall to the ground with his arms outstretched. Two deputies immediately descended on him and began punching him in the head and kneeing him in the groin.

The group surrounding the man grew to 13 sheriff's deputies as several appeared to kick, hit, and punch him dozens of times over a two-minute period.

In the two minutes after the man was stunned with a Taser, it appeared deputies kicked him 17 times and punched him 37 times and struck him with batons four times. Thirteen blows appeared to be to the head. The allegedly stolen horse stood idly nearby.

[...] Deputies said the Taser was ineffective due to his loose clothing and a use of force occurred.
"I can certainly understand the concerns in the community based on what they saw on the video," McMahon told NBC4. "I'm disturbed by what I see in the video. But I don't need to jump to conclusions at this point, until we do a complete and thorough investigation. If our deputy sheriff's did something wrong, they'll be put off work and they'll be dealt with appropriately, all in accordance with the law as well as our department policy."