Can cops be murderers too?

Stephon Clark who was 22 years of age and a father of 2 was shot and killed by police in Sacramento, California last Sunday (March 17th, 2018). Police fired 20 shots at Stephon after claiming to have saw a weapon, which later turned out to only be a cell phone which officers claim Stephon walked toward them brandishing as a firearm..

When do we draw the line and call this for what it is.

           Murder 

https://www.npr.org/sections/thetwo-way/2018/03/22/596051907/video-shows-sacramento-police-shoot-unarmed-black-man-in-grandparents-backyard

If not now, when