Arrest warrants were issued by state authorities in Louisiana for four Baton Rouge police officers who were connected to the city police force's Street Crimes Unit, according to a source familiar with the investigation.

The Street Crimes Unit has faced scrutiny in recent weeks after allegations of mistreatment of detainees, including at a now-shuttered police warehouse that officers allegedly called the "brave cave," according to complaints made against the department.

The arrest warrants however, are not related to the "brave cave" case, according to the source, but for a prior incident.

The FBI announced over the weekend they are investigating the Baton Rouge Police Department (BRPD) following allegations that some officers "abused their authority."

The New Orleans FBI Field Office, the Civil Rights Division and the U.S. Attorney's Office for the Middle District of Louisiana have opened the probe, with investigators "reviewing the matter for potential federal violations," the FBI New Orleans said in a statement on Friday, while urging anyone with information on the case to contact them.

The department's police chief reported the allegations of the "brave cave" to the FBI, a source familiar with the investigation said Tuesday.

At a tense Baton Rouge City Council meeting on Wednesday, police chief Murphy Paul said that in past incidents he has looked to hold police officers who don't follow the law accountable.