The Umbrella star was in negotiations to perform in the Maryland region shortly after riots broke out there following the death of Freddie Gray, who sustained fatal injuries while in police custody in April (15).

Emails obtained by the Baltimore Sun newspaper appear to show Rihanna had hoped to walk with the protesters before performing a free show, and was willing to travel to the area by train to avoid attracting too much attention.

The documents show a communication between a police officer, who had spoken to Rihanna's team, and the head of the force's media relations unit about the negotiations.

An excerpt reads, "(A representative for Rihanna) advised that Rihanna wants to walk with the protesters as well as perform a free concert. He added that she will be arriving by plane and in an effort to divert press/media she will be traveling to the city by train (or by car if necessary)... (He) stated that they had hoped to secure some extra police security and was directed by the Governor's office to seek assistance through Communications."

The publication cites a "situation report" published on 1 May (15) with revealing the outcome of the negotiations, quoting the message as saying, "Possible Rihanna Concert at Penn & North... No time given. Police are claiming they have no permit so it will not be allowed."

Pop legend Prince played a gig in Baltimore days later on 10 May (15) and performed a special song he had written about the unrest in the area.