Do you have the link to the shooters posted here?
No, he doesn't and neither do you.
The loss of two police officers in two different, but closely related circumstances, is tragic, but your speculation that it was BLM is no more legitimate nor illegitimate than the speculation it was ******* Nazis or Sovereign Citizens. At this point, no one knows anything except what was posted in your link:
"The Des Moines Police Department said suspect information is being developed. The agency didn’t immediately release any other information but said a news conference was planned for 5 a.m."