1. Rxc4! clears the a2-g8 diagonal for the b3-bishop and threatens a discovered check, ie. Rc3 dsc+.
1. Rxc4 Kh7 (an attempt to escape the discovered attack) Bc2 pins the queen to the king.
1. Rxc4 Kf8 2. Rc8#
1. Rxc4 Kh8 2. Rc8+ Kh7 3. Bc2 +-
1. Rxc4 bxc4 2. Bxc4+ forks the king and queen