Can I get in trouble for playing a practical joke?

So tonight, me and my friend were really bored so we decided to play a practical joke. We made a collage of all these boys who are in a frat. We took all these unatractive pictures from facebook of them and put it together. We put some kind of mean quotes under it as well, they were pretty funny tho. We went to the frat house and put the letter on the porch, we were hiding our faces so we looked a little bit like robbers. But right as we were putting the letter, some one came out. We ran to the car and drove away. We scared that our number plate was down. Can we get in trouble with the police? Also we did all this just as a joke; we have nothing against those guys. We use to party with them as well. We just played a practical joke out of boredom. Please help me, what are the problems we have to face?