The Philadelphia Police Department is expected this week to begin the process of firing police officers whose racist or offensive Facebook posts were documented in an online database, according to three sources with knowledge of the situation.

The anticipated terminations would represent the most significant step in a scandal that has attracted national attention, and led to protests and public outcry.

The sources, who asked not to be identified discussing a pending matter, said as many as 13 officers were expected to be suspended with intent to dismiss beginning Friday. It was not immediately clear who the officers are or what they may have posted.

Commissioner Richard Ross said last month that 72 officers had been taken off street duty pending the department’s investigation into the posts, and that he expected dozens to face internal consequences and at least several to be fired.

Ross did not respond to requests for comment Wednesday.

Capt. Sekou Kinebrew, a police spokesperson, said only that the department’s investigation into the scandal — which encompasses more than 3,000 posts allegedly made by more than 300 officers — is ongoing.

John McNesby, president of Fraternal Order of Police Lodge 5, declined to comment.

The database, published online June 1, was compiled by a group called the Plain View Project. It highlights Facebook posts or comments from officers in Philadelphia and seven other police departments: York, Pa.; Phoenix; Dallas; St. Louis; Twin Falls, Idaho; Denison, Texas; and Lake County, Fla.

The researchers behind the database — led by lawyer Emily Baker-White, who formerly worked at the Federal Community Defender Office in Philadelphia — said they flagged posts allegedly made by officers that the researchers considered racist, supportive of violence, or otherwise offensive.

Their list included more than 500 current and retired Philadelphia officers, about 330 of whom were still on the force when the database went live.

Ross has repeatedly said that he was troubled by the posts and that they could undermine public trust in the department. Other city officials also condemned the posts, and District Attorney Larry Krasner said his office was reviewing the database to determine which officers should be placed on a list of police with credibility issues.

The police officers’ union said last month that it did not believe anyone should be fired as a result of Facebook posts, signaling that it may fight any terminations via its arbitration process.

Ross said last month that the investigation into the posts was being conducted by the department’s Internal Affairs Division and the law firm Ballard Spahr.

He said the department was “trying to deal with some of the worst postings first,” such as those that appeared to be racist, intolerant, or condoning violence. He said the investigation would be conducted in stages, with some officers disciplined as the probe continued to sort through other, possibly less offensive, examples.

Ross did not specify how long the investigation might take, but said each post would be evaluated to see whether it was constitutionally protected speech under the First Amendment or if it violated the department’s social media policy, which says in part that employees “are prohibited from using ethnic slurs, profanity, personal insults; material that is harassing, defamatory, fraudulent, or discriminatory.”

The fallout from the scandal in other affected locations has taken different forms.

And last month in St. Louis, Circuit Attorney Kimberly M. Gardner placed 22 officers on a list of police whose testimony will not be used by prosecutors, according to the St. Louis Post-Dispatch.