Possible Clues:

• Franz ---, Austrian composer
• Austrian composer of the Trout piano quintet
• 'Trout' quintet composer
• A noted work of his remained unfinished
• Man behind bars butchers butchered?
• Soprano - safe bet to retain focus for composer
• Composer disturbed brutes outside church
• Salieri-trained originator of the romantic lied
• 'Unfinished Symphony' composer
• Classical composer — namely Parry, perhaps?