July 6, 2010— -- The San Joaquin Valley in central California is one of the world's most productive agricultural regions. It's an arid desert irrigated to make a land of plenty, where crops such as grapes and garlic are grown.
But on March 12, 2004, the city of Fresno was stunned by the revelation that the devil had seemingly sowed his seed in their midst.
What started out as a routine custody dispute at a house in the west-central area of the city suddenly and inexplicably escalated into the worst mass murder in Fresno's history.
Nine people were found dead inside the house, their bodies piled in a back room. In the tangled heap, there were two adults and seven young children -- three of whom were under the age of two.
Watch "Primetime: Family Secrets" Tuesdays at 10 p.m. ET.
Police arrested 57-year-old Marcus Wesson, who emerged from the residence with blood on his clothes. Neighbors' accounts led police to believe that Wesson controlled his family in a cult-like manner, and that he possibly had fathered several of the deceased children with his own daughters and nieces.
Two of those nieces had come to the house to get their children, which ended up triggering the mass murder.
But several of Wesson's surviving sons rose to his defense, telling reporters that that Wesson was a wonderful father who loved his children and never could have hurt them.
Exactly how the purported "wonderful father" also could be one of the most deranged monsters in American history is the strange question at the heart of this story.
CLICK HERE to see photos of the Wesson family and photos from the day of the massacre
The answer lay in Wesson's extraordinary power to control the minds of his wife and children. It seemed to be a power that placed him in the company of such madmen as David Koresh, who led his followers to their fiery death at Waco, Jim Jones, whose flock committed mass suicide in Guyana, and of course, Charles Manson, who turned flower children into random killers.
Wesson was all of this, and more. To help understand how he was able control his family so completely, "Primetime" sat down with Wesson's wife Elizabeth Wesson and five of his surviving children.
Wesson's sons -- Adrian, Serafino and Dorian -- told ABC News correspondent Jay Schadler that only now, years after the crime, could they see their father for what he was: psychotic, delusional and narcissistic.
Sons Recall Childhood Under Wesson
Thirty-five-year-old Dorian Wesson told Schadler, "He said that ... if you've seen God, you've seen me."
Adrian Wesson, 34, added, "He was God. That's just the way it was."
"God" wore dreadlocks, and commanded absolute obedience. Serafino Wesson, known as Fino, once sneaked a spoonful of peanut butter and received a beating with a cable wire that lasted for almost 20 minutes straight.
Some punishments would last for weeks, or even months.
"A 30-day punishment involved ... well, 21 hits on your person and then that's one in the morning and then one in the afternoon and one before you went to bed," said Serafino Wesson, 25. "Now imagine getting that for 30 days straight."
Wesson mixed ruthlessness with indoctrination. His Bible studies and prayer sessions would last for hours. His children told ABC News that they didn't realize they were living in a hellish situation because they were born into it and had no outside influences to teach them otherwise.
The roots of Wesson's obsessions snaked back four decades to the day he staged a homemade wedding ceremony. The bride, Elizabeth Wesson, was just 8 years old.
Elizabeth Wesson told ABC News that she believed Marcus Wesson when he said the Lord chose her to be his wife. She reveled in the attention he showered upon her.
"He said that I belonged to him -- that I was his wife already," Elizabeth Wesson said.
By 14, Elizabeth Wesson was pregnant, and by 26 she had given birth eleven times.
Over the years, Marcus Wesson collected bizarre beliefs and welded them together to create his own vision, which he imposed upon his growing family. He wrote his own version of the Bible, in which he claimed that Jesus was a vampire. He told his family "the end was near."
For years, he warned his wife and children to prepare for the day when the devil with a badge and a blue uniform would show up at their door. Until then, he sequestered and home-schooled the family in a series of hideaways along the California coast. One of the places was Tomales Bay, south of San Francisco, where he anchored a rusted-out sailboat and hid the children.
Gypsy Wesson, 26, told ABC News that Marcus Wesson would leave the children unattended on the boat for four or five months at a time below deck so no one would see them and ask why they weren't in school.
"It felt like being in a prison," Gypsy Wesson told Schadler. "Very depressing -- like, hopeless. And you felt trapped ... nowhere to go."
Two hours south of Tomales Bay was another hideout, in a remote spot high in the Santa Cruz mountains. Wesson had the family pitch a huge army surplus tent and they lived in the squalid camp for the better part of 12 years, away from the prying eyes of neighbors, social workers and police.
For the boys, Bible studies were enforced with whips and sticks. For the girls, Wesson was teaching them a different kind of lesson: something he called "loving."
Gypsy Wesson and Kiani Wesson told ABC News that their father started touching them sexually when they were seven or eight years old.
Gypsy Wesson said she felt it was wrong, but Kiani Wesson didn't know otherwise.
"I didn't know anything else and I thought it was all right," said Kiani Wesson, 33.
When asked why their mother didn't stop the abuse, Kiani Wesson said that she felt her mother was powerless.
"She'd been with my dad since she was eight years old," said Kiani Wesson. "So I felt that she was pretty much, you know, caught up in the same thing."
Psychiatrist Edward Hallowell, director of the Hallowell Centers in New York and Boston, watched "Primetime's" interviews with the Wesson children and said Wesson used fear as a manipulative tool.
"What he basically did was create this crucible of fear," said Hallowell. "He used fear, extreme fear, to get these kids to act completely counter to their self-interest."
As the kids grew older, they were allowed to get jobs as long as they turned all their money over to their father.
"Such was his control over their minds that he could even send them out into the world and they didn't blow the whistle," said Hallowell. "All they had to do was walk into the police station or even just tell their boss ... about what's going on at home and the jig would have been up."
On March 12, 2004, what began as a routine domestic call -- two distraught mothers barred from seeing their children inside 761 West Hammond Avenue -- quickly escalated.
Two of Wesson's nieces, who had borne his children, were there to take them back.
Raw police audio from the scene captured the voices of the two women screaming at Wesson for their children.
Wesson stood at the door, telling the women that he wouldn't give up the kids "under kidnapping conditions," and calmly told police he would cooperate. Then he disappeared into the house.
Two of the children inside the house, 8-year-old Illabelle and 13-month-old Jeva, belonged to Kiani Wesson, Marcus Wesson's oldest daughter. Kiani Wesson was inside the house that day, and watched as her children, along with her closest sister Lise and six other Wesson kids, were led into a back bedroom. She would never see them again.
No one is exactly sure what happened next. Police claim they heard no gunshots.
Kiani Wesson tearfully told ABC News that she thinks Sebhrenah Wesson, her 25-year-old sister, pulled the trigger and killed her son, sister, nieces and nephews.
"I think that he had her take everybody, and then he took her life," said a tearful Kiani Wesson.
Then Marcus Wesson reappeared at the front door of his house, which was by now surrounded by cops and screaming family members, who had feared the worst when Marcus went inside.
Fresno Police Officer Eloy Escareno arrived on the scene just as Wesson was emerging from the house, hands in the air, his clothes stained with blood.
As Marcus Wesson was arrested and led away, Officer Escareno entered the house and was the first to confirm everyone's fears: nine bodies lay in a tangled pile on the floor: Sebhrenah, 25, Elizabeth "Lise," 17, Illabelle, 8, Jonathan and Aviv, both 7, Ethan, 4, and Marshey, Sedona and Jeva all less than two years old.
Sebhrenah and Lise were the daughters of Marcus Wesson and Elizabeth Wesson. All the other children were kids Wesson fathered either with his daughters or nieces.
"I broke down and started crying," Officer Escareno told ABC News. "I was trying to wipe away the tears ... but the father in me was ... just overwhelmed at that point."
Surviving Wesson Kids Struggle to Heal
As news of the murder exploded across Fresno, most of the media was focused on the killer in dreadlocks. But local TV reporter, Alysia Sofios, was fascinated by the survivors who were defending their father.
Within days, Sofios arranged a meeting with Fino Wesson in an alley behind a local burger joint. At that point, all he could think about was defending his dad. He was determined to clear his name, even though Marcus Wesson now was facing charges of murder, rape and sexual assault.
Like cult members not yet deprogrammed, his sons were loyal.
But Sofios saw beyond the robotic exteriors and knew the Wessons were hurting. She also knew Elizabeth, Gypsy and Kiani had never been to school and had no money -- so she invited them to share her apartment.
But the decision to harbor the Wesson women was not without consequence. She had crossed an ethical boundary that every reporter knows.
"I became part of the story," Sofios told ABC News. "I'm not supposed to do that. I even knew ... I wasn't supposed to do it. I was even telling myself I wasn't supposed to do it ... the minute I hung up the phone. ... I kind of sat on my bed and mourned the loss of my reporting career."
Today, Sofios still works at the same Fresno TV station and is still roommates with Gypsy Wesson. In fact, Sofios considers herself part of the family. She's written a book about their incredible story, called "Where Hope Begins."
Both Kiani and Gypsy Wesson have new daughters of their own, and Gypsy Wesson's little girl is named in honor Alysia.
Fino Wesson and his wife have two children, and one on the way. Looking for a way to honor the murdered children, he has set his sights on becoming a police officer.
In June 2005, a jury convicted Wesson of nine counts of murder and multiple counts of rape and sexual assault. He was sentenced to death row at San Quentin State Prison. Elizabeth Wesson and the kids no longer have any contact with Marcus Wesson, though he still lives unrepentantly in their nightmares.
Watch "Primetime: Family Secrets" Tuesdays at 10 p.m. ET.