[Responsibility2nd]

They were sent on a health and welfare check. For a health and welfare check it is assumed that the resident is home but may be incapacitated or need assistance.

You're making an assumption. Yes the 911 call was for a welfare check, but did the two cops get that message? Apparently not. Both of them treated the scene as a possible burglary. And acted appropriately.

[MrEdd]

What is your evidence for this accusation of previously unreported criminal negligence on the part of dispatch?