Can you be charged based solely upon a third party's statement? Probably not. But, it might be enough to get the police to look into the matter.
If you tell a friend that you just molested a little girl and your friend tells the police, you can bet they will come calling! If you tell a friend that you etched your name in a bus bench and the friend passes this along to the police, I doubt they will do more than shrug. So, it all depends upon the context and the nature of the alleged offense as to what might happen. An arrest - based only upon the words of the friend - would be highly unlikely (next to impossible).