Democratic presidential candidate Bernie Sanders joined the crowd of poilticians and activists calling for a federal investigation into the Chicago Police Department and added that any officials who were aware of a potential cover-up should resign.

"I join with those calling for a federal investigation into the practices of the Chicago Police Department," Sanders said in a statement released Friday. "Furthermore, any official who helped suppress the videotape of Laquan McDonald's murder should be held accountable. And any elected official with knowledge that the tape was being suppressed or improperly withheld should resign. No one should be shielded by power or position."

The increasing calls for the investigation are propelled by the release of the dashcam video in November that showed the fatal shooting of 17-year-old Laquan McDonald by former Chicago Police Officer Jason Van Dyke.

Critics attacked Cook County State's Attorney Anita Alvarez, former Chicago Police Supt. Garry McCarthy and Mayor Rahm Emanuel for the 13 months it took to charge Van Dyke and release the dashcam video to the public. Many activists also claim the three officials were involved in a cover-up of the case, which all of them have disputed.

After the video was released, Sanders released another statement saying Americans should do more than chant "Black Lives Matter" and "put actions behind those words."

"All Americans should be sicked by the video of Laquan McDonald's murder," Sanders said in the Nov. 25 statement. "As a nation we must do more than just echo the phrase Black Lives Matter. We must put actions behind those words. Actions that will bring about the fundamental reform that is needed in the face of this crisis. Criminal justice reform must be the civil rights issue of the 21st century and the first piece must be putting an end to the killing of African Americans by police officers."

Sanders' latest statement comes on the heels of rival Hillary Clinton's call for a probe into the police department's practices. Clinton spokesperson Brian Fallon told The Chicago Tribune Wednesday that she is "deeply troubled" by the shooting and the "outstanding questions" raised by it.

The same day Clinton voiced her support for the investigation, the White House released a statement in support of Emanuel, saying he has demonstrated a "personal commitment" to reforming the city's police department.

Emanuel himself did not come out in support of the Justice Department investigation until Thursday. Until that day, he said he was against further investigations.