You saw a crime being committed. Downside to that is you then have to take them to the police, not the police out to take them from you.
As others have been saying, that is not an apology given what you said.
Cycling Dan, have been in a similar situation as you gave earlier, where you were left feeling as though you were in the wrong. I'd say that the only difference is I was following up on what was at the time an active case. He was the "officer in charge of the investigation". Followed being hit by a car, drunk driver thought I was actually a bus, so it was safe to pull out.