I thought you were supposed to follow the law. The law says that you need a warrant or his permission to enter and search his house. Furthermore, in
Weeks v. United States, 232 U.S. 383 (1914), it was decided that evidence gained through the violation of someone's fourth amendment rights is NOT admissible in court.
1) You didn't have the right to search the house
2) He cannot be convicted using what you found there
I know that what he had was illegal, but what you did was just as illegal. I expected better of you.