In order to establish negligence as a Cause of Action under the law of torts, a plaintiff must prove that the defendant had a duty to the plaintiff, the defendant breached that duty by failing to conform to the required standard of conduct, the defendant's negligent conduct was the cause of the harm to the plaintiff, and the plaintiff was, in fact, harmed or damaged."
I'd say that the Bolings have a pretty good case for proving negligence. Regardless of what happened after the LEO arrived, his first mistake was unacceptable. When You are going into a possible life & death situation, you'd better make darn sure you are where you are supposed to be.
My prayers are with that family, and I hope justice is done on their behalf.