Chess : Mates in 4 Moves

When I was a high school kid at Baguio City High School, a friend show me a chess puzzle. The puzzle it to construct a game that will checkmate Black in 4 moves from the starting position. Black should copy moves made by White. The initial moves in mind was

1. P-K4 P-K4
2. B-B4 B-B4
3. Q-R5 Q-R5
4. QxP check
NOT mate because of 4. . . . K-Q1

After few minutes of taught, I made the following solutions:
1. P-Q4 P-Q4
2. Q-Q3 Q-Q3
3. Q-KR3 Q-KR3
4. QxB checkmate

There are two (2) more solutions.
The idea is to capture the Queen's Bishop on the fourth move.
Can you solve it?