Butch's wife, Barbara, spoke to me from Florida today, and dropped this little tidbit: Police detectives gave Butch two lie detector tests after Maura went missing. They were told he flunked the first one and passed the second. She believes he failed the first one due to his health complications, which included high blood pressure, diabetes, a-fib, and COPD.
Before you get too excited about this info, you should know that lie detector tests are not admissible in court (usually) and are basically just a tool for detectives to push a suspect into a confession. The tests measure bio-feedback so his health would certainly have been a factor. To me, Butch is not a likely suspect, and seems to be a good samaritan who got caught up in a big case.
Keep in mind, at the time Butch lived there with both Barbara and his mother, Violet. And Maura's accident was in plain view of three homes. Not easy for a 300-pound guy to commit a crime in those circumstances.
To his dying day, Butch believed Maura was picked up by someone, possibly a traveling companion, due to how quickly her disappearance happened.