Thicker than water : a novel / Megan Collins.

Julia and Sienna Larkin are sisters-in-law, connected by Julia's husband and Sienna's brother, Jason. More than that, the two are devoted best friends and business partners, believing that theirs is a uniquely unbreakable bond. To Sienna, her protective brother can do no wrong, and although Julia knows he's not perfect, they've built a comfortable life and family together. Recently, Jason has been putting in long hours to secure a promotion at work, so when his boss is found brutally murdered--his lips sewn shut--the Larkins are shocked and unsettled, especially as local gossip swirls. A few days later, Julia and Sienna's lives are upended when Jason gets into a car accident and is placed in a medically induced coma. Worse, the police arrive with news that he's the prime suspect in the murder investigation. With Jason unable to respond--and with Julia and Sienna working to clear his name--the two women find their friendship threatened for the first time: Sienna staunchly maintains her brother's innocence, but as their investigation uncovers a complicated web of secrets, Julia is less sure she's willing to defend her husband.