Critics of police welcome Facebook Live and other tools to stream video

New York

AFTER back-to-back killings of black men by police officers last week, scores of African-Americans declared on social media that they would be equipping themselves with a powerful tool: Facebook Live.

Facebook's new live-streaming service and similar apps, like Twitter's Periscope, offer the ability not just to record video but to broadcast events as they are unfolding.

Viewers saw this first-hand when a woman streamed her boyfriend, Philando Castile, clutching his bloodied chest during a traffic stop in Falcon Heights, Minnesota, on Wednesday, moments after he was shot by the police. As of Thursday, the video had been watched nearly four million times.

Those wrenching images on Facebook, along with the police shooting of Alton Sterling a day earlier in Baton Rouge, Louisiana, uploaded to YouTube and other platforms, reinforced the power of video, especially when l…