There was something about a girl who saw him at the door and she saw blood on his shirt. It was on one of the CT or NY papers website.
Here ya go ...
http://www.newhavenindependent.org/archives/2009/09/was_that_annie.php
<snip> A stranger held open the door for her. He seemed odd — and he had blood on his shirt.
It could well have been a coincidence. But the encounter inside the garage at 10 Amistad St. spooked her.
When she later learned that it happened the same day that murdered graduate student Annie Le went missing — she knew it was time to call the cops.
She ended up telling her story to the FBI.