I am often asked: how can I make sure I get home safe after I am pulled over by the police? Following the killings of Alton Sterling and Philando Castile, I feel I should know the answer to that question – but I don't.

You might think I'm the ideal person to answer: I served four years in the US Marine corps' version of Swat, and 11 years as a Baltimore police officer, detective, sergeant and shift commander. I've participated in innumerable car stops, 400-plus arrests and every training event that I could. And yet, I have no idea how to respond to that basic question.

Following Castile's death, my friend, Frank MacArthur tweeted: "Brother got gunned down for no reason. He had a burned out tail light. Complied. Did EVERYTHING cop asked. STILL not good enough. For America." He is right. Based on what we know from available reports, Mr Castile did nothing that could have jeopardized his life. There is nothing he could have done differently.