Down To The Bone

Caitlin Rother

Kensington Pub

June 24^th, 2025

Down to the Bone by Caitlin Rother just came out, but the real-life case on which it’s based also gained nationwide attention again recently due to parallels to the Bosch Legacy Season 3 episodes, featuring the disappearance of the Gallagher family.  In the true story, Joseph and Summer McStay and their two young sons, Joey Jr. and Gianni, went mysteriously missing from their house in Fallbrook, California, in February 2010.

The San Diego County Sheriff’s Department (SDSD) investigated their disappearance as a missing persons’ case for three years, after finding no blood or any physical evidence of foul play in the house. The SDSD let the case go cold, deciding the McStays had gone voluntarily to Mexico, even though there was no activity on their phones or credit cards.  About nine months later, their skeletal remains were discovered in the high desert of San Bernardino County, with holes in their skulls, along with a sledgehammer consistent with the injuries. Summer’s bra was sliced in half and her sweatpants and panties were pulled off. A year after that, Joseph’s business associate, Charles “Chase” Merritt, was arrested for their murders, and he was later convicted. After an emotional sentencing hearing, during which Merritt maintained his innocence, the judge imposed the death penalty. 

Elise Cooper: Why this story?

Caitlin Rother: My previous book, Death on Ocean Boulevard, was about the Rebecca Zahau case, which happened in 2011. This case happened in 2010, and the same homicide unit investigated both, so they were in the news at the same time. I pick cases that look like they will be high-profile with high emotional interest. It is also very unusual for an entire family to go missing. 

EC:  Do you think the Sheriff Department was inept?

CR: The San Diego Sheriff’s Department (SDSD) drew heavy criticism for both investigations. I look at these books as part 1 and part 2 because they both involve allegations of confirmation bias. That’s when investigators focus on a piece of evidence, premise or a theory that leads them to believe one thing, and no matter what other evidence comes up to the contrary, they just won’t move from it. 

With the Zahau case in Death on Ocean Boulevard, the SDSD detectives essentially decided it was a suicide within four days, and to this day the agency has not moved from that determination despite a civil jury verdict finding the brother of Zahau’s boyfriend responsible for her death. In the McStay case in Down to the Bone, the Sheriff’s Department thought this family went voluntarily to Mexico and nothing moved the detective off that premise. Lieutenant Ryan Smith from the San Bernardino County Sheriff’s Department said he would have gone after search warrants harder, approaching a different judge or trying again when the family did not turn up after a certain time. 

EC: What about Merritt’s polygraph exam?

CR: Lt. Ryan said the SDSD also “kind of missed the mark” with the questions they asked Merritt, because they were geared towards the family being missing rather than murdered. The SDSD claimed they were only allowed to do that type of investigation because they had no probable cause to investigate it as a homicide, but a lot of people thought the SDSD dropped the ball. 

EC: What was the role of Joseph’s gun found in a felon’s car in Las Vegas?

CR: That evidence never got to the jury, so it was one of the dots the defense was never allowed to connect for the jury, i.e., that the gun could have been taken from Joseph or used to get the family out of the house.  The family’s remains were found in two graves, where there were two sets of truck-tire tracks with different wheelbases, one leading to each grave. How was it that someone got a family of four out of the house, and to the desert where they are found with holes in the back of their skulls from a sledgehammer? The gun could have played a role in that, but this is one of the lingering mysteries of this case.

EC: What can you tell us about the theft of money in this case?

CR: The defense made repeated allegations at trial that Dan Kavanaugh, Joseph’s other business associate, stole money from the business, sold the business without authorization, and kept that money too. But Lt. Smith said that even if Kavanaugh did steal money, he could not be prosecuted because Joseph is dead, so there is no victim on which to base the case. The prosecution also accused Merritt of fraudulently cashing checks written on Joseph’s business account. 

EC: Do you agree there were several people of interest, but the sheriff had tunnel vision?

CR: According to the SDSD, they did investigate these people.  The question is how thoroughly.  The department refused to be accountable or transparent and wouldn’t do any interviews for this book. This certainly does not help if they were worried about deflecting criticism. Nor does it help them look more credible or legitimate. 

EC:  How would you describe Joseph?

CR: Everyone loved him. He was a good guy, a loving father and husband. He gave people money, and in my view was way too trusting. I don’t think he always had good judgment when it came to choosing the people around him. 

EC: How would you describe Summer?

CR: I only know about what family and friends said in witness interviews, that she was smart, very protective of her children, mistrusting, and had fallings out with Joseph’s family members, as well as her own. She also filed a complaint with Child Protective Services, which caused further divisions. Joseph was hoping to go to counseling to improve their marriage and to ease some of these tensions.

EC: What do you want to say to readers about this case?

CR: First, and most importantly, I still don’t know who killed this family. Joseph was so trusting, maybe he let the wrong people get too close to him. There were several conflicts in the prosecution’s logic, such as why was Merritt’s phone on when he was allegedly burying the bodies, but off when allegedly cleaning up the crime scene? Then there was the unidentified DNA found at the grave site. We still don’t know whose DNA it is because it was never run through the federal CODIS database, only that it doesn’t match the McStays or Chase Merritt. I wanted to raise questions and challenge the investigative process and show the holes, conflicts, and discrepancies of the prosecution’s case. I hope this book opens readers’ eyes and causes them to question their preconceived views of this case. 

EC: Next book?

CR: Hooked, the first book in a new thriller series, based in La Jolla, California, comes out in January. The main characters are a surfing homicide detective and a female investigative journalist, who investigate the suspicious deaths of two executives at a biotech company that is developing a new sex drug, billed to perpetuate the infatuation and excitement of new relationships. The investigation also reveals an underbelly of corruption in this beautiful beach community. 

THANK YOU!!

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