LOS ANGELES (CBSLA.com) — Never-before-seen footage has revealed a covert unit within the Los Angeles Police Department designed to weed out “bad apples.”

The LAPD’s Special Operations Division tackles the most serious crimes, such as planted evidence, drugs, thefts and even murder, as in the case of former LAPD Detective Stephanie Lazarus.

“The mission was about weeding out the bad police officers. The bad apples. The ones that tarnish the badge,” an unidentified member of the unit told CBS2’s Rick Garcia.

He, in essence, lives a double life, working undercover out of a secret location to investigate his colleagues.

“I can’t let people know what I do because I could compromise officer safety and the success of our investigations,” he said.

“I’m guessing that it must be somewhat of a burden to carry around the information that you have to carry around that you’re not allowed to share with the people that are closest around you,” asked CBS2’s Garcia.

The officer said: “Very much so. That’s probably the toughest thing about this assignment is having to be evasive to your friends and family.”

Surveillance video reveals crimes the unit said they have captured, including murder-for hires, propositioning of prostitutes and nabbing an off-duty officer who took illegal weapons from someone he never booked.

Because of the work involved and the double life officers are required to preserve, only an elite group is recruited.

“We’re obviously looking for somebody with the highest level of integrity and character. Someone who has knowledge of policy, procedure, law so when they’re out there, they can make the right decisions. They know what they are looking for,” LAPD Capt. Edward Pape said.

As a sergeant, Chief Charlie Beck was one of the division’s original undercover investigators.

“Well, it goes back to the mid-’80s,” Beck said. “What I did as an investigator … I did murder-for-hire. I did sales and narcotics. I did planting of evidence on arrestees.”

The type of investigating required digs deep.

“They’ll do it either through surveillance. They may do it using undercover operatives. They do it in ways that a more traditional detective wouldn’t be able to do,” Beck said.

The chief says they exonerate many more employees than they implicate, and while the rank-and-file doesn’t know who serves on special operations, they do know the unit exists.

“This is one of the ways that we make sure that we can be as good as we can be,” said Beck.

When asked what the biggest misconception is about the Special Operations Division, the unidentified officer said: “That we’re playing a game of gotcha. That we’re out to catch our own people doing bad things. I know as a member of this police department that the overwhelming majority of people are out here doing the right thing.”

While Beck could not disclose how many officers are in the Special Operations Division, he did say it’s the largest of its kind. In fact, L.A. handles investigations for police departments that do not have their own units.