What forensic signs specifically relating to sailing might be left on a boat to prove the drowning of the husband was homicide. The wife claims she awoke to the boat adrift on the open sea, no husband.
I'm a screenwriter who knows nothing about sailing, but needs clues that my brilliant detective could see to prove homicide.
Well there can be many samples that could be left behind that could be used for clues. Fingerprints, hair samples, blood samples could be left at the site that could used to identify the suspect. Forensic scientists do experiments on samples left on the crime scene to determine the possible suspects. You need to leave samples in two places so they can have sample to compare the evidence to.