BELLEVUE, Tenn. -- A Bellevue family now knows what caused their son's death, but it took nearly six months to find out.

There were problems surrounding the investigation into Brandon McMahon's death. The state medical examiner said his office is partly to blame for not doing the proper tests.

McMahon died from hypertrophic cardiomyopathy. It appears he had an enlarged heart muscle.

The family said their repeated phone calls to the medical examiner's office weren't returned until the Channel 4 I-Team began investigating.