You have been invited to a poker game where each of the other players (Alex, Bert, Carl, Dave) is a knight, knave or liar. The players introduce themselves as follows:

Player 1's statements:
1. Bert is a knight.
2. I am Alex.

Player 2's statements:
1. Alex is a liar.
2. I am a knave.

Player 3's statements:
1. Carl is a knave.
2. Dave is a liar.

Player 4's statements:
1. I am Dave.
2. Bert is a knight.
3. Carl is a knave.

Determine who makes which set of statements and whether each one is a knight, knave or liar.