mystery...please help!

[sjr8ut]

Hi. I hope that I did not make a huge mistake getting this car. I have a '94 that I just bought. It has a vibration/nosie problem at highway speeds. I was rotating the tires yesterday to make sure that they were not the cause of the highway noise. When I took off the left front tire, I noticed a cut wire. It is the wire to the wheel speed sensor. Someone took an eight inch section out of the wire and took the bracket that holds the wire to the strut as well. This was not all, after removing the tire, I noticed a single ball bearing on the floor of my garage directly underneath the left front tire area. I found a recept in the car from a popular brake and muffler chain that indicates that back in July, the left front wheel bearing, inner and outer seals, and brakes were replaced--to the tune of 600 bucks. The receipt also said that the wheel speed sensor on that side was faulty but the owner did not want to replace it. This leaves me with a bunch of questions that maybe some of you who are smarter than myself could answer. First, why would someone cut a section of wire from the wheel speed sensor? Is this done after it is found faulty so they know which one to fix or is something else going on? Next, where did the single ball bearing come from? If the bearing went bad, would one just fall onto the floor after removing the tire? Does the car use this kind of ball bearing? Last, could a bad wheel bearing cause vibration/noise at 65 mph plus, without having any play in the wheel or any other problems? Please help!