The Night Ferry by Michael Robotham

Alisha "Ali" Barba, a detective with the London Metropolitan Police, is almost recovered from injuries suffered on the job when she gets a note from her estranged high school best friend, Cate, asking her to attend their school reunion. Ali meets up with Cate at the reunion and Cate asks for her help. She tells Ali that someone wants to take her baby (she's eight months pregnant). Before Ali can learn more, Cate and her husband are killed in a car accident. Ali also learns that Cate was faking her pregnancy. Ali's allegiance to Cate and their lost friendship provide Ali with the drive to find out what exactly Cate was involved in. In addition, Ali's search leads her into danger and to question if she's done more harm than good with her investigation. Ali, a thirtysomething woman from a Sikh background, is an interesting main character and the plot is intriguing enough that you'll keep turning the pages. In The Night Ferry, Ali gets help from her retired superior, Vincent Ruiz, who was featured in both of Robotham's previous novels, Suspect and Lost.