Second: One of the last phone calls MC made or received was with the murderer as well, (police won't tell us who last phone call(s) were too).
Alt: I'm with you on your theory except this final phone call. Wasn't there an aunt that commented on FB that WC had a visitor prior to getting off work/school? "Someone" could have stopped by the salon and said "I need to drop my truck off at the....let's say....tire shop. Can you pick me up and give me a ride home when you get off work?" Then they have a prearranged meeting time and place, no need for phone contact.