(CBS DETROIT) – New questions are emerging tonight about how police de-escalation tactics work and when they are used following the Grand Rapids police shooting death of Patrick Lyoya.

Protesters are calling for them to be reviewed in the wake of new video released by Grand Rapids police.

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That video shows one of their officers holding 26-year-old Patrick Lyoya on the ground and shooting him in the back of the head.

Adriana Diaz reported from Grand Rapids with the latest:

The deadly encounter escalated in a matter of minutes.

The question is, should the officer have acted differently to de-escalate, based on his training?

In the Grand Rapids police policy, it states that an officer should always try to control a situation using verbal commands.

If a subject does not comply, only then can the officer escalate to use physical force.

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The amount of force should be quote “reasonable” and “based on the level of resistance encountered.”

In terms of *de-escalation* it only says “as the subject begins to de-escalate or lessen the resistance offered, the officer must de-escalate in a similar manner.”

When Lewis Langham, a Michigan Criminal Procedure Professor and former State Police Detective, was asked if the officer acted in line with the de-escalation policy, he said, “There was substantial compliance to that policy based upon what was taking place – the verbal commands given by the officer, they were ignored and it escalates up from there. I didn’t see any major problems with the officers actions necessarily as it relates to whether or not he did what he was supposed to do, for the most part, in trying to control the situation without using any type of excessive force or violence and then things obviously got out of control.”

Protesters and family attorney Ben Crump say it was the officer who escalated the situation.

Some in the community told us police need more de-escalation training, along with diversity and mental health training.

The officer is currently on paid leave. Its now up to the Michigan State police to investigate whether the he complied with policy. The Kent County Prosecutor, will then determine if charges are warranted.

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