I had the police out to my house a few years ago, in England. A person that had been attacked had my telephone number on their call records, they wanted to now if I knew anything. I told them I didn't have a clue what they were talking about, and said I couldn't help further, and if they wanted to send their questions to my brief we could discuss further.
If you would like a lawyers take on this-
YouTube - Don't Talk to Cops, Part 1
A tip. Never, ever talk to the police without a solicitor present.