The Supreme Court has ruled on many occasions that police do not have any constitutional duty to protect citizens from harm, even in life-threatening situations. Few are aware that "to protect and serve" means [their masters] protection of anyone BUT you (e.g. even the public).
Warren v. District of Columbia, 444 A.2d. 1, D.C. Ct. of Ap. (1981): Three women were brutally attacked after calling 911, and police failed to show up. They sued and it went to the SCOTUS, and they ruled that police have no specific legal duty to protect individual citizens, only a general duty to the public at large.
Lozito v. New York City (2012): Lozito was stabbed on a subway while NYPD officers nearby just looked on from behind a closed door. They only did something once Lozito himself managed to subdue the attacker. Again the court ruled that officers have no legal obligation to protect citizens [or anyone for that matter].
Castle Rock v. Gonzales, 545 U.S. 748 (2005): The U.S. Supreme Court ruled, 7–2, that a town and its police department could not be sued under 42 U.S.C. § 1983 for refusing to enforce a restraining order, even though the refusal led to the murders of a woman's three children by her estranged husband.
DeShaney v. Winnebago Cty. DSS, 489 U.S. 189 (1989): In this case, a young boy was repeatedly abused at the hands of his father, something that county Social Services was aware of, but made no effort to remove the child. His mother sued once the four-year old entered a vegetative state, and the Court ruled that that the state did not have a special obligation to protect a citizen against harms it did not create.
In short, police are often the sole boot-licking authority that keeps totalitarians in power. They are not held to any standard the public would deem worthy, nor are they special, honourable, or helpful to the general public in many instances. There are far more evidences of police violating constitutional rights, daily, than there are of police helping the general public (issuing fines for victimless crimes does not count).