On May 17, Mammadov's lawyer wrote on Facebook that his client had been subjected to torture while in police custody, posting a picture of what he claimed to be a handwritten letter from Mammadov.

"They brought me to the office of the chief officer, where there were 7-8 officers in civilian clothes," the letter reads. "They immediately began punching, slapping and kicking me and asking me why I had taken pictures of the graffiti, who was my associate and so on. However, I was not able to answer their questions as I lost my hearing and shortly thereafter lost consciousness."

The letter went on to say that Mammadov signed a confession presented to him to end the beatings.