"The city of Berkeley will be doing the investigation, along with, in parallel with the St. Louis County. And our overall goal is to project the truth to the residents."
Hoskins also says the case shouldn't be compared to that of Michael Brown, who was also shot dead by a white police in neighboring Ferguson in August.
"We reviewed the video and it appears that there was a gun pointed at the officer before the officer fired. But we've got to complete our investigation before we take a position."
The shooting has already sparked clashes among police and protesters around the gas station where 18-year old Antonio Martin was shot and killed.
The suburb of Berkley, unlike Ferguson where there is a predominantly white police force, the majority of Berkeley's police officers are black.
Michael Brown's death and a subsequent grand jury decision not to charge the officer have already triggered nationwide protests.
Animosity toward police has also led to two police officers being gunned down in New York.
