By the mid-1980s, he was a major leader. During the early 1990s, Gusmão became deeply involved in diplomacy and media management, and was instrumental in alerting the world to the massacre in Dili that occurred in Santa Cruz on 12 November 1991.
On 14 November, the Navy blockade of Dalmatian ports was challenged by civilian ships. The confrontation culminated in the Battle of the Dalmatian channels, when Croatian coastal and island based artillery damaged, sank, or captured a number of Yugoslav navy vessels, including Mukos PČ 176, later rechristened PB 62 Šolta.
On 18 November 1991, the Croatian Community of Herzeg-Bosnia was established in Mostar. Mate Boban was chosen as its president. Its founding document said: "The Community will respect the democratically elected government of the Republic of Bosnia and Herzegovina for as long as exists the state independence of Bosnia and Herzegovina in relation to the former, or any other, Yugoslavia".
On 22 November 1991, Mercury called Queen's manager Jim Beach to his Kensington home to prepare a public statement, which was released the following day: Following the enormous conjecture in the press over the last two weeks, I wish to confirm that I have been tested HIV positive and have AIDS. I felt it correct to keep this information private to date to protect the privacy of those around me. However, the time has come now for my friends and fans around the world to know the truth and I hope that everyone will join with me, my doctors and all those worldwide in the fight against this terrible disease. My privacy has always been very special to me and I am famous for my lack of interviews. Please understand this policy will continue.
On the evening of 24 November 1991, about 24 hours after issuing the statement, Mercury died at the age of 45 at his home in Kensington. The cause of death was bronchial pneumonia resulting from AIDS. Mercury's close friend Dave Clark of the Dave Clark Five was at the bedside vigil when he died. Austin phoned Mercury's parents and sister to break the news, which reached newspaper and television crews in the early hours of 25 November.