That is weird, might have been anything. Please don't take this the wrong way, but have you considered that it may have just been a police
helicopter? I mean, you mention that there were police officers asking someone questions nearby - maybe a crime was committed at her house or
something and the police were there asking questions and the chopper was out searching for the criminal?
I'm not trying to dismiss your notion of a UFO, but maybe it wasn't? I guess we'd really have to see it for ourselves.

