A crowd marched the sidewalk in Danville, chanting against the white noise of a recent rush hour. “Justice for Tyrell,” they strained to be heard. “Justice for Tyrell Wilson!”

It had been one year since Wilson was fatally shot on Sycamore Valley Road — the second man to die after an encounter with the same Contra Costa County sheriff’s deputy.

Both men were people of color struggling with mental illness in an affluent town that’s 80% white — factors that thrust the cases into the national discussion around race, mental health and policing. The killings brought to light a familiar trend: In Bay Area suburbs, reactions to police shootings tend to be more muted, and there generally are fewer oversight mechanisms to identify problem officers.