CHICAGO — The Chicago mayor’s office, police and the body that investigates police shootings closely coordinated their response in the months after a white officer fatally shot a black teenager in 2014, emails released Thursday revealed.

The messages clearly indicate that advisers to Mayor Rahm Emanuel knew within months that the case could be politically explosive.

Thousands of emails were released in response to open-records requests from The Associated Press and other media regarding 17-year-old Laquan McDonald, who was killed in October 2014 after being shot 16 times. Few communications from Emanuel’s staff mention him directly – though several refer to him by the acronym “MRE.”

A video of the officer shooting McDonald – which was not made public until more than a year later, on Nov. 24 – led to protests and repeated calls for Emanuel to resign. The officer has been charged with murder and pleaded not guilty this week at his arraignment.

Emanuel has denied ever seeing the video prior to its release, a contention many activists have said they do not believe. The emails do not appear to contradict Emanuel’s claim, though they show how City Hall grew increasingly concerned that the video could pose a major public-relations problem.