That's in some states, set by case precedent, not actual law. And it's actually any murder of a uniformed officer, which is different than an unintentional killing (ie. manslaughter).

It effectively means any second-degree murder charge gets upgraded to first-degree. The theory is that because it is a uniformed officer, you therefore have time to premeditate the killing as a means of escape. The killing itself is evidence of premeditation.

No such thing exists in Canada. We don't even have felony murder for being an accessory to a crime before the fact, where the crime results in a death (even if it's one of the perpetrators that is killed). We are very very soft on violent crime in this country. That will change soon as people get tired of more and more crime at the hands of the elite's pet migrant population.