A Washington, D.C. police officer who worked as a motorcycle escort for White House officials and other dignitaries was moved to administrative duty Wednesday after he allegedly was overheard making threatening comments toward Michelle Obama, according to several police officials.

The police department’s Internal Affairs Division is investigating the alleged comments and notified the U.S. Secret Service Wednesday, said the officials, who spoke on condition of anonymity because they were not authorized to give details of the investigation.

The motorman allegedly made the comments Wednesday morning as several officers from the Special Operations Division discussed threats against the Obamas. It was not immediately clear where the alleged conversation took place or exactly how many officers took part in the conversation.

During that conversation, the officials said, the officer allegedly said he would shoot the First Lady and then used his phone to retrieve a picture of the firearm he said he would use. It was not immediately clear what type of firearm was allegedly shown.

Police officials declined to identify the officer. Officials from the U.S. Attorney’s office declined comment.