This is interesting ... that the cause of death could be known by Monday. That suggests to me that the cause of death may be obvious by looking at the body. If there is too much decomposition, I doubt they would say that.
"Due to the state of decomposition to the body it will be sent to the medical examiner's office in Memphis. They will compare dental records that we have to Ms. Swift to determine if there is a positive identification."
According to Box, the medical examiner's office will most likely have identification results by Monday as well as a cause of death."
(same link as above)