At the Royal Opera House, an extraordinary concert was held to premiere the new symphony by the genius Maestro 'Farid'. The concert was billed as an 'immersive sensory experience': as soon as the music began at exactly 9:00 PM, all the lights in the main hall were completely turned off, and the symphony played automatically in pitch darkness for 15 minutes until 9:15 PM. Guests and VIPs sat in their seats blindfolded in the dark. After the performance ended and the lights came back on, the Maestro did not come out to greet the audience. Minutes later, he was found strangled with a piano wire in his private 'Studio B' overlooking the back corridor. The forensic report confirmed that the death occurred precisely between 9:00 and 9:15 PM. The killer had a time window of only 15 minutes, and every suspect claims they were tied to their location.