The governor is facing felony charges for alleged abuse of power.
Jesse Byrnes 08/19/14 03:45 PM EDT
The incident took place not far from Ferguson, Mo.
U.S. Attorney Richard A. Callahan said secrecy is crucial for the investigation.
Clashes erupted on the first night National Guard troops were deployed.
Chef Sam Kass is also an adviser to Michelle Obama.
Sen. Roy Blunt said state investigators should be given time to probe Michael Brown's death.
The petition now has enough signatures to warrant an official response.
"We will not use a curfew tonight," Gov. Jay Nixon (D) said.
A private autopsy shows all bullets hit the front of the teen.
Nixon said he took the action after "coordinated" attacks on civilians, officers.