SAN DIEGO (CBS 8) - A new book written by a former business partner of Joseph McStay levels some bombshell accusations against Joseph's wife Summer in the months leading up to the McStay family's mysterious disappearance in February 2010.
Chase Merritt, an ex-con who had worked with Joseph McStay in his fountain-making business, claims that in the months leading up to the McStay family's disappearance, Joseph had been concerned his wife was possibly poisoning him, after he continuously suffered a mysterious illness that drained him of his energy and often left him bedridden.
While Joseph McStay's father, Patrick McStay, confirmed to CBS News 8 that his son did suffer from some type of unexplained illness, he is unequivocally blasting the notion that his daughter-in-law Summer had anything to do with it.
"There was nothing to it, because it just didn't make any sense," Patrick McStay said, speaking from his home in Texas.
In an interview with the British newspaper The Daily Mail, Chase Merritt also suggests that Joseph and Summer McStay were having major relationship problems, casting suspicion on Summer, whom he describes as having a fiery temper.
Again, Patrick McStay rejected the notion Summer had anything to do with the family's disappearance.
"I'm sure just like any other marriage they had problems. And was Summer very possessive of Joey? Yes. Did she like sharing him with people? No. I'll go along with all of that. But to leap to killing somebody? No!" he said.
"I think that would be the craziest thing in the world," Patrick McStay added. "She's got the man she truly loves. I truly believe she loved my son, without a doubt."
Joseph and Summer McStay, along with their two sons, ages 3 and 4, seemingly vanished without a trace in February 2010, after they were last seen leaving their Fallbrook home. Nearly four years later, last November a motorcyclist out for a ride in the Mojave Desert stumbled across what turned out to be the skeletal remains of all four members of the missing McStay family. Authorities have not named any suspects in their disappearance or murders.
Patrick McStay also told CBS News 8 that he believes his son trusted Chase Merritt as a business partner.
Court records show that Merritt is a two-time ex-con with a criminal history that includes burglary, grand theft, receiving stolen property and several arrest warrants.