> I was shocked to learn innocent people get convicted because they talked to the cops.
You should read up on Project Innocence casefiles:
http://www.innocenceproject.org/know/
Dennis Fritz in particular, he volunteered to give hair samples which were used to create circumstantial evidence against him:
http://www.innocenceproject.org/Content/Dennis_Fritz.php
Had he not done that, had he not gone in to talk voluntarily to the police he probably would not have lost 11 years of his life, lost seeing his daughter grow up. All for talking with the police. Do not talk to the police. The cost can be unimaginably high.