"white mass shooters get detained but cops don't know how to NOT murder black people!"
no, that's not true:
no, that's not true:

John Allen Muhammad & Lee Boyd Malvo shot & killed 17 people from February 16, 2002 to October 24, 2002 in the Baltimore-Washington Metropolitan Area & Arizona. both detained.
Markeith Loyd murdered his pregnant girlfriend & then murdered Lt. Debra Clayton in Orlando, Florida. detained. sentenced to life in prison.
Timmy Earl Kinner stabbed 9 people at a toddlers birthday party. among these people was the 3 y/o birthday girl who died. taken into custody, as you can see.
sources:
https://en.m.wikipedia.org/wiki/D.C._sniper_attacks
https://amp.cnn.com/cnn/2019/10/23/us/markeith-loyd-murder-sentence/index.html
https://www.ktvb.com/amp/article/news/crime/boise-timmy-kinner-mass-stabbing-competent-trial/277-b6a1ba2c-89e0-479c-b06d-3abcb0f13776
https://en.m.wikipedia.org/wiki/2017_Mississippi_shootings
http://newjersey.news12.com/story/34869898/crockam-gets-life-in-prison-for-murder-of-lakewood-patrolman
https://www.google.com/amp/s/www.blufftontoday.com/jaspersuntimes/news/2017-08-10/hampton-county-man-gets-35-year-sentence-shooting-police-officer%3ftemplate=ampart
https://www.10tv.com/amp/article/news/local/quentin-smith-sentenced-life-without-parole-killing-westerville-officers-2019-dec/530-3c165ab7-9b28-46cd-836e-9d7a3cbca90e
https://www.orlandosentinel.com/news/breaking-news/os-deputy-barbara-pill-death-penalty-rejected-20170330-story.html?outputType=amp
https://en.m.wikipedia.org/wiki/D.C._sniper_attacks
https://amp.cnn.com/cnn/2019/10/23/us/markeith-loyd-murder-sentence/index.html
https://www.ktvb.com/amp/article/news/crime/boise-timmy-kinner-mass-stabbing-competent-trial/277-b6a1ba2c-89e0-479c-b06d-3abcb0f13776
https://en.m.wikipedia.org/wiki/2017_Mississippi_shootings
http://newjersey.news12.com/story/34869898/crockam-gets-life-in-prison-for-murder-of-lakewood-patrolman
https://www.google.com/amp/s/www.blufftontoday.com/jaspersuntimes/news/2017-08-10/hampton-county-man-gets-35-year-sentence-shooting-police-officer%3ftemplate=ampart
https://www.10tv.com/amp/article/news/local/quentin-smith-sentenced-life-without-parole-killing-westerville-officers-2019-dec/530-3c165ab7-9b28-46cd-836e-9d7a3cbca90e
https://www.orlandosentinel.com/news/breaking-news/os-deputy-barbara-pill-death-penalty-rejected-20170330-story.html?outputType=amp