What Do You Do When Police Stop Looking for Your Daughter?

Chuck Cox is a dad who will never give up. The retired inspector for the Federal Aviation Administration from Washington state has taken over the hunt for his missing daughter's remains since Utah police officially closed the case earlier this summer into the disappearance of Susan Cox Powell. Susan's friends have launched their own support team and are appealing to the public to help in an all-out search for Susan, presumed murdered by suicidal killer dad Josh Powell, who hacked at his two young sons with an ax before torching the home where all three perished.

Cox and a private investigator are poring over leads flushed out during Chuck's recent trip along a 400-mile stretch of I-84 from Oregon to Utah, where he and daughter Denise Cox Olsen handed out flyers, talked to gas station attendants, and quizzed waitresses at roadside diners. The flyers feature photos of Powell, his brother Michael (a possible accomplice, who also committed suicide) and the two cars the brothers were driving the week Susan vanished from her home in West Valley, Utah, in 2009. The problem is that Susan's body could be just about anywhere.

The Cox family is just one grappling with the devastating aftermath of the bizarre phenomenon of family annihilations in America, which often involve suicide by the killer dad. Police continue to hunt for Shane Franklin Miller, who they believe killed his wife and two young daughters in his rural home in California's Humboldt County in early May. Weeks later 63-year-old Anthony Alvarez, described by friends as a devoted dad, shot to death one grown daughter and wounded another before committing suicide in the central California town of Orosi. The number of U.S. murder-suicides, including familicides, jumped 30 percent from 2007 to 2011 to some 12 incidents each week, according to reports tracked by the Violence Policy Center.

The Powell case is one of the most troubling family annihilations I researched for my book Killer Dads: The Twisted Drives That Compel Fathers to Murder Their Own Kids. Susan, 28, vanished just weeks before Christmas over three years ago after an early dinner prepared, unusually, by Josh. Susan was suddenly lethargic and ill after eating, leading her family to believe she was poisoned by her always-angry husband. Josh then claimed he took their sons -- Braden, then 2, and Charlie, 4 -- on a camping trip after dinner, even though it was well below freezing and the ground was covered with snow, and that Susan was gone when he returned. One of the boys would later tell a teacher that "Mommy was in the trunk," during the trip. After Susan vanished, Josh emptied her IRA account, made arrangements to collect a $1.5 million life insurance policy he had taken out on his wife and moved back with his sons into his father's home in Washington. He was never charged in Susan's disappearance. Over a year later, as he faced the likelihood of permanently losing custody of his kids to Susan's concerned parents, he torched a rented home he had booby-trapped with tanks of gasoline while the boys were visiting.

In the months leading up to her disappearance Susan recounted her increasing trouble with Josh in a series of chilling emails to friends. The charmingly loopy boy-man who had wooed Susan while she was still a teenager in Puyallup, Washington, had allegedly morphed over the eight years of their marriage into a petulant, threatening control freak. "If I die it may not be an accident, even if it looks like one," she warned in a hand-written will locked in her office desk that police would find far too late.

Josh once told a work acquaintance that a perfect murder would end with the disposal of a body down one of the abandoned mine shafts that pepper the Utah desert. Police checked some 400 of them but failed to find Susan's body. They later uncovered information that Josh's brother may have helped him dispose of the body in Oregon, or somewhere along the highway.

Chuck Cox and his wife, Judy, are deeply religious and believe that Susan is now far from pain and has been reunited with her sons in death. But they are haunted by the vision of her remains lying exposed, vulnerable, alone, and want to bury her with the boys. They and a devoted circle of supporters are left to grapple with the fallout of one of a stream of devastating domestic violence crimes that we tend to accept as simply part of violent American life.

"It's time we find Susan," said Chuck. "With more information and more people looking at it, the more likely we are that someone figures out where she is. I have to keep looking."