We don’t know when or where the person who contacted police “saw something” worth reporting. It might’ve been a suspicious activity earlier or even later in the day after he’d changed his clothes. He could’ve been a stranger who acted oddly during the search. But the suspect had to have been wearing the clothes as described during the murder because that’s known by Libby’s photo. What’s important is the suspect be identified by someone who remembers him looking like the sketch from two years ago because by now his clothing, his weight, his facial hair, the hair on his head all would likely be different.