The Pier: A DCI Garner and DS Brierton Murder Mystery

A woman's body is found hanging under Cleethorpes Pier.  It quickly becomes apparent it's a murder case. DCI Garner and DS Brierton are assigned to investigate. As they progress with their investigation, gathering evidence and forensics, two potential suspects come to their attention. But who is the killer? Which suspect, if either, had the motive to kill?