Cool Puzzle (Forced Mate) From an Actual Game

Checkmate in at most 5 moves: [ 1. Rd8 Bg5 2. Rf7+ Kg8 3. Rg7+ (or Rxe8+) Kh8 4. Rg8+ (or Rxe8+) Rxg8 5. Rxg8# ]
When you are mystified about who is on move, consider the following options:
1. Which side needs to be on move for it to be a puzzle? Usually there is only one answer.
2. Which side plays from the bottom to the top of the diagram? In game positions the answer is usually clear. You may assume that side on move when nothing else is specified.
3. Anything wrong with assuming that white is on move? A standard convention for problems and endgames is that white starts. Therefore most publications in that category will not telll you who is on move.
You can figure it out now, can you?