I don't think any killer would be so smart to set up another man while leaving a blood stained incriminating evidence in a car. If Michael were to be pulled over, he would have been busted. Driving around with the necklace is like walking around with a confession letter. I think Ella's instincts are right to think that Michael was set up. Since Auggie directed David's search, he probably hid it. Another possibility is Vanessa killed Sydney after she found out Michael was having an affair. Heather Locklear's appearance does provide credibility to the series, but I don't think it is enough. I think she boarded a sinking ship that she can't be fixed before it is canceled. It is a win-win for her since she gets to say some great lines in her attempt to save the show.