This is the second in a 3-part series that offers an inside look at the FBI on its 100th anniversary. FOX News was granted rare access for the reports, which examine the lives of bureau agents. Click here for Part 1, a look at the next generation of agents in training at the FBI Academy in Quantico.

PHILADELPHIA — Even as the FBI tackles terrorism at home and abroad, career agents are handling old-fashioned investigative work, taking on violent criminals and fighting to keep drug dealers off the streets.

For Part 2 of FOX News' series marking the 100th anniversary of the Federal Bureau of Investigation, FOX gained exclusive access to one of Philadelphia's premier drug and violent crime task forces, in which FBI agents and city officers work hand in hand.

Click here to see exclusive video of a joint raid conducted by the FBI and police in Philadelphia.

FBI Director Robert Mueller touted the tough work his agents perform in Philadelphia, which he said is typical of the agency's 56 field offices.

"You are investigating often violent criminals who think nothing of utilizing a weapon to evade capture," Mueller said.

And the men and women who work these streets are well aware of what is at stake.

"Every time an officer steps away from their desk and out on the streets, they are placing themselves at risk," said Janice Fedarcyk, who runs the FBI's Philadelphia field office.

FOX News was allowed to shadow a bust. We saw the squad assemble a team of 15, as well as additional uniformed officers as backup. The day before the bust, they used a program called Project Pinpoint to identify crime hotspots, gunshot victims and other threats in the neighborhood.

That and other relevant information, including the weapons and other equipment they will take, go into an operations plan, the minute-by-minute road map for the bust.

It can take weeks, even months, to gather enough intelligence for an arrest warrant, and even after all that hard work there is no way to know whether the mission will be successful.

In this case, the meeting time was set for 5:30 a.m. At 6 a.m., a briefing was held in preparation for the attempted arrest a half hour later. Each agent and officer had an assignment, from forcing entry into the home to covering the front and back.

Philadelphia Police Sgt. Joe DelGrippo led the briefing. Their target, he said, was Lyndell Jackson, also known as Lyndell Westbrook, a repeat offender alleged to be dealing drugs whose last arrest was in 2002. A search warrant recently executed at the target address on Glenmore Avenue turned up heroin, marijuana, crack cocaine and a handgun.

"All right, let's go get 'em," DelGrippo told the assembled officers and agents.

The agents arrived at the house and banged on the door, yelling "Police!" They broke into the house and moved into the first floor. They checked the basement, but found no one. They moved upstairs to check the second floor, which also was empty.

All clear, no Lyndell.

Even with good intelligence, a search doesn't always pan out, and the FBI's hunt continues.

"We've got a new alias now that he's using so we'll research that," said FBI agent Judy Tyler. "He has to rely on people that he knows to communicate — for funds, for his drugs — so we'll try and follow all that up."

After a long process of investigation and securing a warrant, agents may be frustrated, but they know their work isn't finished until a suspect is in custody.

"Our job's not done til we get 'em," said Del Grippo.

For more in-depth reports on the FBI, check for the next installment: Life After the FBI.

Catherine Herridge is an award-winning Chief Intelligence correspondent for FOX News Channel (FNC) based in Washington, D.C. She covers intelligence, the Justice Department and the Department of Homeland Security. Herridge joined FNC in 1996 as a London-based correspondent.