Plot holes (SPOILERS)

How was the killer able to frame the dude in the opposite building? Sure the killer had a listening device in Hutton's apartment but he didn't have CAMERAS in there too. And it's never clear how he was able to know what the dude across the way was doing.

Also, near the end, when Hutton called her boyfriend from the killer's house and learned that the cop wanted to meet with them both in one hour -- why the hell did Hutton decide to go home first?