Cathy L. Lanier will certainly have her hands full as the NFL’s new head of security. (Katherine Frey / TWP)

D.C. Police Chief Cathy L. Lanier announced Tuesday she is resigning after 10 years on the job to become the head of security for the National Football League. But what, exactly, does that job entail?

On the surface, the job involves making sure the league’s biggest events run without incident. Here’s the NFL’s job posting, which Pro Football Talk uncovered in May after Jeff Miller announced his resignation:

“The Head of Security for the National Football League is charged with supervising all operations and activities of the NFL Security Department,” the posting states. “The position requires constant high-level coordination with the Committee on Stadium Security and Fan Conduct and other league committees as needed, Commissioner’s office, executive staff, club ownership and personnel. In addition to internal coordination, the Head of Security must work effectively with International, federal, state, and local law entities such as the Federal Bureau of Investigation, Secret Service, Homeland Security, and local law enforcement to ensure the security of the NFL’s venues, fans, players, staff and infrastructure. This executive will also be the primary supervisor of investigative programs, as well as oversee event security (including the Super Bowl and international games), game integrity programs, and department administration. He/she will take the lead in assessing security issues within the League and assigning and/or identifying the correct resources as they arise.”

Considering the number of law-enforcement agencies that have jurisdiction in Washington — there’s the Metropolitan Police Department, National Park Service Police, Secret Service, U.S. Marshals and Metro Transit Police, plus others — and the coordination involved between those entities during major events (Fourth of July celebrations, presidential inaugurations, etc.), Lanier would seem to be a good candidate for the job. Plus, she has the law-enforcement experience that would seem to be a prerequisite for the position. Miller, for instance, previously was the commissioner of the Pennsylvania State Police before taking the NFL job in 2008.

“We are excited to welcome to our team an individual of Cathy’s talent and extensive record of accomplishments,” NFL Commissioner Roger Goodell said in a league-issued statement. “Cathy joins us with a well-deserved reputation of being a tremendous communicator, innovator and relationship builder.”

But that’s far from all Lanier will need to bring to the job, as she’ll be tasked with investigating incidents involving league personnel that have the potential to cast the league in a bad light.

Miller came under fire in 2014 during the league’s handling of the Ray Rice affair, in which the former Baltimore Ravens running back punched out his then-fiancee in an Atlantic City hotel elevator. An unnamed law-enforcement official told the Associated Press that he had sent a copy of the security video that showed Rice assaulting his fiancee to the NFL, addressing it specifically to Miller. But Miller denied that he had seen the video until TMZ published it in September 2014, and a nominally independent investigation failed to uncover evidence to the contrary.

But apart from spearheading investigations of high-profile misdeeds by the league’s players, the NFL head of security also sits at the top of a hierarchy that reaches into nearly every aspect of professional football. The Post’s Kent Babb and Adam Goldman tried to decipher the NFL’s complex security flow chart in 2014, as the Rice brouhaha was unfolding, calling the NFL’s security arm “an intricate and largely secretive three-layered security force — mainly comprised of former federal agents — in charge of staying in front of the league’s problems.”

The uppermost level of the NFL’s security department is based at the league’s New York City headquarters and is comprised of about a dozen employees — the NFL won’t give a precise number — most of them decorated former law-enforcement officials. Jeffrey Miller, its chief security officer, was once Pennsylvania’s state police commissioner; his lead investigator is John Raucci, a former assistant director of the Federal Bureau of Investigation, where he was the bureau’s top agent in London and helped coordinate the 2012 Olympics. Despite the bona fides, only the most potentially damaging cases — Michael Vick’s involvement in a dog fighting ring, former Ravens linebacker Ray Lewis’s connection to a double murder in 1999, the New England Patriots videotaping opposing teams’ signals in 2007 — typically lead to loafers-on-the-ground investigations by the league office’s security staff.

Another specialist within the league office, a former FBI agent, oversees security for the NFL draft and the Super Bowl, the league’s most visible events, often making preliminary plans years in advance. Another official supervises security at each of the league’s 32 stadiums, according to an individual familiar with the staff’s organization. …

Each NFL team is assigned a contractor, along with an associate investigator, to act as the league’s eyes and ears (many teams hire their own in-house security experts to protect their interests). Of the consultants assigned by the league, many have experience in federal law enforcement agencies — most commonly the FBI — and their directive is to establish knowledge of and comfort within the local legal setting. They get to know the area’s information brokers, and after player arrests or potential incidents of misconduct, the representative ferrets out information — often details that would never be made public — with the intention of sharing it with the league office.

Lanier will now sit at the top of that pyramid, one that reaches into nearly every aspect of a players’ life.

“For all the years that I was in the NFL, NFL Security and the NFL’s ability to protect its integrity — the so-called ‘protection of the shield’ — was unmatched in American business,” former Indianapolis Colts executive Bill Polian told ESPN in 2014. “I mean, you did not step out of line in the NFL … The office was there to make sure that the clubs, the players, the reputation of the NFL remained unsullied.”