Personally I think any officer acting outside of his departments policy and committing a crime should face the same charges and penalties as a "regular person" would.
As a somewhat unrelated note, and something that is quite often overlooked when people criticize police in general, is the completely different level of "normal" we operate under. It's by no means an excuse, and isn't anything someone should hide behind, but consider I make 100 contacts a month, some of those being tickets, some arrests, community contacts, verbal warnings, or just assisting motorists with disabled vehicles...98 of those will be completely mundane interactions with nothing interesting to report. Then we have a Friday night where at the very start of our shift we get a call of a traffic collision, which instead ended up being an attempted carjacking and kidnapping by a guy with a cannon of a revolver who ended up being shot as he began to point it at the officers on scene. I arrived and watched those same officers then render medical aid and provide cpr to the same guy, trying to save his life after he tried to take theirs.
Follow that up with our Saturday night where my partner and I make a stop on a possible dui driver. Contact him, get him out of the car to start a dui investigation, only to end up with both of us wrestling him to the ground and into handcuffs as he tried to get back to his car for who knows what.
It's a world people really don't understand, and getting a peek in every so often through news stories rarely gives you an actual idea of what happens on a regular basis, and what it takes to try and keep yourself in a place mentally where you can go from verbally reprimanding that teenager who just had to take that phone call, to helping the guy who blew his tire on a pothole, to then fighting for your life with the next person you contact who was "just another stop". Bit of a tangent I know, and rather unrelated to your question, but just something for people to keep in mind when they do question every officer out there.
And while I don't fully agree with
@Edgar Allan Pillow's point above about sticking together for the sake of it, he does have a point that you do create a bond with a certain group of people that are the only ones that go through what you and your family goes through. Having that bond, and knowing that you would lay down your life to protect them, as they would for you, does sometimes skew viewpoints and what we may overlook for someone else. Not saying it's right or wrong, but many people would look the other way for family, even when things are illegal or immoral, and wouldn't think twice about it because it's family.