Weapon in the Watermelon by Dale Mayer

When a young couple is attacked while prepping for a catering job, it seems like the family is dealing with a long-running curse—one that ends in murder. … Doreen can’t stop meddling, so, when she finds out that that the young woman’s mother is an unsolved murder case, Doreen has her cold case to work her way into Mack’s current investigation.
But, like all her cases, nothing is quite so simple. While Mack is dealing with the death of the dead chef, Doreen is working behind the scenes to sort out all the different family factions. Meanwhile she must also sort out a gift for Nan’s birthday. Somehow Doreen manages to mix the two together.

Now if only things would go smoothly from here on in—but of course not they don’t. With the animals involved, the chaos is even wilder