By KEVIN DOLAK
The 2010 disappearance of the McStay family, whose skeletal remains were discovered in shallow graves in the California desert last week, led a former North Carolina radio host to embark on a three-year, globe-trotting mission to solve the mystery of what became of them.
The remains of Joseph McStay, 40, and his wife, Summer McStay, 43, along with their two young sons Gianni McStay, age 4 and Joseph, age 3, were found earlier this week in shallow desert graves outside Victorville, Calif. The family mysteriously vanished from their home in 2010, and what happened to them has plagued radio host and author Rick Baker ever since.
Baker, who published the book "No Goodbyes: The Mysterious Disappearance of the McStay Family" in February, has been chasing international leads on supposed sightings of the family and interviewing the couple's family, friends and business associates.
After being told by police of the discovery, Baker told ABCNews.com that "it was very hard for me to put arms around" the fact that the family was murdered.
"I thought I would meet them one day," Baker said. "I've traveled around the world to what I thought were verified sightings. I thought they were part of my family, and I grieved when I heard. Never in my wildest dreams or nightmares could I have supposed that the entire my family would be dead."
A video of a family matching the description of the McStays crossing into Mexico four days after their disappearance had been obtained by police, but on Friday police said that it was never confirmed to be the McStays, and it was unclear whether the people seen in the video ever crossed back into the United States.
Such leads and supposed sightings were what sent Baker traveling to Belize, Mexico, Haiti, the Dominican Republic and other countries chasing the McStays. He said his interest in the case was aroused during an interview with Michael McStay, Joseph's brother, in May 2011 for his San Diego talk radio program.
Since then, Baker has interviewed family and friends of Joseph McStay, and the business partners in the missing dad's interior decorative fountain business. Baker said he read through thousands of the McStays emails, leading up to just days before their disappearance.
Michael McStay sobbed at a press conference on Friday, and said the past four years have been a "tough road" for relatives who held out hope the family would be found safe.
"It's not really the outcome we were looking for," he said, "but it gives us courage to know they're together."
On Friday, police said the manner of death has been ruled homicide, however, they declined to comment on the possible cause of death, or whether the family may have been targeted by a drug cartel.
When detectives entered the family's home in 2010, they found rotten eggs on the counter and the family's two dogs in the backyard. Police later found the family's vehicle abandoned near the U.S.-Mexico border, prompting authorities to wonder whether they had crossed into Mexico.
Baker said he thinks the evidence points not to a drug cartel, but an amateur attempting to stage the crime, so it would appear to be a drug-related cartel hit on McStay and his family. He said the Isuzu Trooper found near the scene -- along with the scene at the family's home -- was staged.
"Why did they stage the car? A cartel is not interested in staging anything," he said. "The bodies weren't that far off of the main road. A cartel wouldn't want bodies ever to be found, and they wouldn't be just 50 feet off the road. It looks like an amateur, and not a cartel hit."
Despite this new evidence in a perplexing case, Baker said he still doesn't feel any closer to finding out what happened to the McStays.
"No one ever looked at this with a criminal slant," he said "It's more of a mystery now. Who would kill an entire family, bury them, then stage the car?"
Baker has now asked Amazon.com to take his book off the market, and has promised to personally refund the purchase price for anyone who previously bought the book, because he saw it as a means to discovering what happened to the McStays.
"My conscience won't allow me to sell it -- the purpose was for awareness," he said. "Now that we know what happened, I can't sell one more book. I thought they were part of my family, and I grieved when I heard. The people who did this, the death penalty is too good for them. They should be tortured to death."
ABC News' Alyssa Newcomb contributed to this report.