Murder of a Chief Executive Officer

The discovery of a body on an exclusive golf course in the Hamptons was investigated by the local Detective and Medical Examiner. On completion of the investigation all the evidence pointed to an accidental death.
Or was it?
After a chance discussion between the Commissioner and Mario, it was agreed that maybe all was not what it appeared. Mario's team began to reveal incongruities and flaws in the reported timelines and after further investigation, serious fraudulent activities began to surface. However, the timeline conundrum could not be resolved and all the potential suspects had strong alibis.
How was Mario's team going to prove that this was not an accident, but a pre-meditated murder?