Saturday's march was prompted by the death of Darrin Hanna.
He was arrested on a domestic violence charge back in November. Officers used a stun gun on Hanna during his arrest.
He died a week later. The medical examiner found that multiple hits from the stun gun, physical trauma from the officers and pre-existing conditions contributed to Hanna's death.
Jackson called this matter a moral disgrace.
State police determined the officers used reasonable force.
The US Justice Department is conducting an inquiry.
