Democratic presidential hopeful Bernie Sanders added his voice Friday to those calling for a federal investigation of the Chicago Police Department — including his party’s front-runner, Hillary Clinton — but took it a step further.

Amid calls for Chicago Mayor Rahm Emanuel to step down, Sanders also urged the resignation of “any elected official” who knew that a recording was improperly withheld in the high-profile case there of a black teenager fatally shot by a white police officer.

“No one should be shielded by power or position,” Sanders, a Vermont senator, said in a statement about the case of 17-year-old Laquan McDonald that has roiled the city.

Aides said that Sanders had not reached a judgment over whether Emanuel acted improperly, but Sanders’s statement seemed a clear attempt to set himself apart from Clinton, whose campaign this week voiced support for Emanuel, a former top aide to President Bill Clinton.

The dueling statements come at a time when criminal justice and police conduct have been salient issues in the race for the Democratic nomination.

The dashboard camera video showed Chicago police officer Jason Van Dyke firing 16 shots at McDonald during an altercation in October 2014.

The city paid $5 million to McDonald’s family in April but resisted making the video public until ordered to do so by a  judge last month. On Nov. 24, prosecutors charged Van Dyke with first-degree murder and, hours later, the city released the video, sparking heated protests.

Emanuel, who has called the shooting “profoundly hideous,” denied that politics played any role in his refusal to release the video in the months between the shooting and his reelection as mayor in April.

He has said he was following standard Chicago procedure and that evidence should not be released that is “primary to an investigation because it could compromise or taint that investigation.”

In his statement Friday, Sanders said that “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.”

Staff writer Peter Slevin contributed to this report.