Mate in 5 Exercise 28

Black plays and wins in 4 moves https://lichess.org/jJhH68WF/black

1... Ra2+ 2. Kb1 Bd3+ 3. Kc1 Ra1+ 4. Rb1 Rxb1#

The analysis board does checkmate in 5 moves

1... Rf5 2. Rb7 Ra5+ 3. Kb1 Bd3+ 4. Kc1 Ra1+ 5. Rb1 Rxb1#

Source:

https://www.amazon.com/Chess-Puzzles-Advanced-Expert-Level/dp/B0917YQZP1