"I have pledged to the mother and father of Michael Brown that I will be there with them when the decision is announced," Sharpton said at a press conference today.
Sharpton said he is also waiting for a grand jury ruling on the death of Eric Garner, a black man who died while being held in a choke hold by a New York City police officer. That incident was caught on videotape.
He said both grand juries appear to be going beyond the usual protocol of hearing enough evidence to determine whether there should be a trial.
"It is very suspect to us that the grand juries in both cases appear to be improperly expanded to where it is about to prove or disprove the accused rather than seeing if there is probable cause to go to trial," Sharpton said.
"That is not the proper use" of a grand jury, he said. Such tribunals are generally used to deem whether or not there is enough probable cause for a criminal case, while guilt or innocence should not be their focus.
Law enforcement officials fear that the protests could turn violent, as some did in August following the Brown's death. Missouri Gov. Jay Nixon has declared a state of emergency and deployed called the National Guard. The FBI has released a memo to all field offices warning that extremists "will likely" try to infiltrate the demonstrations not only in Ferguson, but elsewhere around the country, and may use the verdict as an excuse to hack public utilities and other sites.