evidence: Black Lives Matter protesters often clashed with federal law enforcement in cities like New York, Seattle and Portland, Oregon, when mandatory curfews went into effect at night. The protesters continued to rally once the sun set, which was in violation of the curfew. When the protesters refused to leave, police sometimes used pepper spray and physical force to disperse the crowds. Many of the conflicts between Black Lives Matter protesters and law enforcement were captured on cell phone video and on live television. "Historically, Black protestors have more often than not been met with governmental oppression and accompanying police violence as a result of our unwillingness to accept the systemic disregard for and mistreatment of Black lives," Dr. Amara Enyia, policy and research coordinator for The Movement for Black Lives, said in a news release.