[sweetliberty]

"That would be true, if the police had proof positive it was GOING to happen"

But suppose this HAD escalated to the point where the robber killed the store clerk. By your reckoning, the cops would bear no responsibility because they had no prior proof that the murder would occur. That is an irrational judgement in my opinion. And you can't have it both ways. If you would concede that had a death resulted, the cops would then be accountable, then they would also have to be accountable for taking that risk in the first place.

[marajade]

"But suppose this HAD escalated to the point where the robber killed the store clerk."

You're asking law enforcement to now predict what might happen after having received a tip to the contrary? If that's the case, its a wonder if people aren't being murdered everywhere ...