Who is innocent and who is guilty?

Inspector Slavco exercise used to go to the hearing to observe the trials.  In this way put to test their reasoning ability.  One of the cases that was found is the following:

We have four defendants:  A, B, C and D. Established the following facts:

1) If A is guilty, then B was complicit.

2) If B is guilty, then C was an accomplice either or is innocent.

3) If D is innocent, then A is guilty and innocent C.

4) If D is guilty, also is A.