What to Know Philadelphia Police Commissioner Richard Ross resigned from his post abruptly on Tuesday, the mayor's office announced Tuesday.

Ross's ouster is tied to a federal lawsuit filed by two female officers. The women say they endured sexual harassment and discrimination.

Ross is a 30 year veteran of the police force. He just weathered a mass shooting of six officers in North Philadelphia.

Editor's Note: Wearing a suit, Richard Ross spoke about his resignation as he left Philadelphia police headquarters Wednesday, here is the latest.

Philadelphia Police Commissioner Richard Ross, a three-decade veteran of the department who last week helped negotiate the surrender of a mass shooting suspect, abruptly resigned on Tuesday, the city's mayor said in a news release.

Mayor Jim Kenney said in a lengthy statement that Ross's resignation "is in the best interest of the department" because "new allegations of sexual harassment as well as gender and racial discrimination among the rank and file have recently been brought to my attention."

"While those allegations do not accuse Commissioner Ross of harassment, I do ultimately believe his resignation is in the best interest of the department," Kenney said.

Ross' resignation is related to a federal civil lawsuit filed by two black female police officers, the mayor's spokeswoman, Deana Gamble, said in an email late Tuesday.

In the lawsuit, which was amended last Friday and lists Ross as a defendant, Cpl. Audra McCowan and patrol officer Jennifer Allen claim they endured groping, verbal harassment and racial discrimination. Allen had breast milk stolen from a police department refrigerator while she was nursing, the suit claims. The women said they were retaliated against for reporting the inappropriate behavior.

The lawsuit cites an alleged text message exchange between McCowan and Ross in February where she tried to report the harassment. The suit claims Ross was dismissive and refused to take action on her report due in part because of an alleged affair the two had before he became commissioner.

"During these conversations, Commissioner Ross also stated he was going to

'school' Ms. McCowan on sexual harassment and indicated that he continues to be upset with her and was getting in the way of redressing her complaints in retribution for her breaking off their two-year affair, which lasted from 2009 to 2011," the lawsuit alleges.

Both McCowen and Allen have been with the department for 15 years, according to the suit. Their attorney told NBC10 they have been on leave since filing their lawsuit.

The attorney also said both of his clients were surprised by Ross's resignation and that they weren't looking for him to resign but wanted to shed light on a serious workplace issue.

Ross has not responded to our request for comment.

Deputy Commissioner Christine Coulter, one of five deputies directly under Ross, was named acting commissioner while a search for a permanent replacement takes place. Coulter is also listed as a defendant in the federal lawsuit.

Police union president John McNesby said the union was "saddened to learn" of the resignation — characterizing it as "sudden."

"The commissioner has served in every rank of the department and is a shining example that hard work and dedication can lead you to the top of your profession. We will miss his passion and guidance for this great police department," McNesby said in a short statement.

The move comes as a surprise as Kenney has often praised Ross, who spent his entire career with the city police department. In an interview with NBC10 on June 27, Kenney gave his full support for Ross's job performance.

"Absolutely. I think he’s one of the finest public servants I’ve had a chance to work with. The thing I like about him is he’s very upfront and he doesn’t pull punches."

"And he tells you what's on his mind. And he has a very strong moral compass. And I think that's what we need in a police commissioner. ... I have all the faith in him since I've had from Day 1."

Mayor Jim Kenney touted the job performance of his police commissioner, Richard Ross, in June, saying Ross “absolutely” has his backing.

Ross spent nearly 30 years on the Philadelphia police force, rising to first deputy commissioner under former Commissioner Charles Ramsey and eventually being promoted as his successor by Kenney in January 2016.

Unlike other police commissioners who jump from big city to big city, Ross served his entire career in his native Philadelphia. He attended Central High School and became a champion for partnerships with other law enforcement agencies across the city. Recently, Ross oversaw efforts to expand diversion programs to connect Philly youth to resources rather than sending them to jail. He called for a holistic approach to reducing gun violence and recidivism, echoing the words of both Kenney and District Attorney Larry Krasner.

"These are real people and real families that are affected by gun violence," Ross said in May. "All of it is senseless. Not some of it - all of it."

Ross recently served as the on-scene point man at an incident in which six of his officers were struck by gunfire by a suspect allegedly armed with an AR-15 in the Nicetown-Tioga section. Ross personally negotiated with the gunman to help end a seven-hour standoff where officers were held hostage.

He also saw the department through dark moments and scandal. Two days after being sworn into his post, a gunman ambushed Officer Jesse Hartnet at a West Philadelphia intersection. Hartnet was shot and seriously injured, but survived the attack. The gunman, Edward Archer, was convicted and sentenced to 48 to 90 years in prison.

In April 2018, the department was thrust into a national scandal when officers were seen on video arresting two black men at a Center City Starbucks with little justification.

Both Ross and Kenney apologized after the incident, with Ross saying he "failed miserably" in the messaging around the arrests.

He initially issued a staunch defense of his officers and their actions.

"I just think that as we work to make this city safer and better we do have to acknowledge that there are still things that we need to work on," Ross said in his apology. "It starts at the top and that starts with me. Messaging is important and I failed miserably in this regard."

Earlier this summer, the Philadelphia Police Department suspended 13 officers with an intent to fire them after a nonprofit group published the results of a two-year review of personal Facebook posts or comments from officers in Philadelphia and seven other U.S. police departments. More than 70 officers were placed on administrative leave after their posts were made public. Nearly all will face some kind of disciplinary action.

Ross repeatedly expressed disappointment if not sadness at the revelation of some 300 racist, homophobic and offensive social media posts by members of his force.

"We have a duty to represent ourselves and our city ... We will not allow this incident to break down the progress we have made and we pledge to do better moving forward," he said in June.

Throughout the turmoil and chaos, Ross was lauded as a steady hand who brought an above-the-fray stoicism to work each day.

Yet Kenney said in his statement that Ross failed to promptly roll out changes required by "a new sexual harassment prevention policy and a series of internal reforms designed to prevent workplace discrimination and harassment throughout the government" enacted last summer.

"While rolling out a new policy understandably takes time, I do not believe the Police Department has taken the necessary actions to address the underlying cultural issues that too often negatively impact women—especially women of color," Kenney said.