The Night We Lost Him by Laura Dave

 Liam Noone built a successful chain of boutique hotels across the country. But he was not so successful in his personal life--marrying 3 times and having children with 2 of those wives. He was also carrying on a decades-long relationship with his first love (who didn't want to marry him). One night, Liam either fell or was pushed off the cliff in front of his California home. The cops think he slipped and fell--and refuse to investigate further. But 2 of his children (from different mothers) think there was more to it and begin their own investigation. They uncover many facets of their father that neither of them had known before--and figure out what really happened that night. It's an interesting story but I liked this author's 800 Grapes better.