Susan Marie Powell (née Cox; born October 16, 1981) is an American missing person from West Valley City, Utah, whose disappearance and suspected murder in December 2009 garnered national media attention.

[5][6] Joshua met Susan Cox, a classmate at his LDS Church Institute of Religion course, during a dinner party at his Tacoma apartment in November 2000.

Steven developed an obsessive infatuation with Susan and followed her around the house with a camcorder, used a small mirror to spy on her while she used the bathroom, stole underwear from her laundry, read her journals and posted love songs online under a pseudonym.

[12] Susan recorded a video in July 2008 surveying property damage she attributed to Joshua, and wrote a secret will that included the statements, "I want it documented that there is extreme turmoil in our marriage" and, "If I die, it may not be an accident, even if it looks like one.

[15] Joshua's mother, Terrica, and his estranged sister, Jennifer Graves, went looking for them at their house shortly after being informed that the children had not been dropped off at daycare that morning.

He claimed he had left Susan sleeping at home shortly after midnight on December 7 and had taken his sons on a camping trip to the Pony Express Trail in western Utah.

Around eighteen hours later, at about 4:00pm on December 9, he called his mother from a new phone whilst on Interstate 84 in Tremonton driving south towards Salt Lake City.

"[21] In August 2012, West Valley City police released documents showing Joshua took actions that were regarded as highly suspicious following Susan's disappearance.

[22] Police interviewed the Powells' elder son, Charlie,[23] who confirmed that the camping trip Joshua described took place;[24] however, unlike his father, he stated that Susan had gone with them and did not return.

[20] Furthermore, Susan's parents, Chuck and Judy Cox, claimed that while at daycare several months after the disappearance, Braden drew a picture of a van with three people in it and told carers: "Mommy was in the trunk.

[37][38] Police also turned their attention to Michael after learning that he had sold his broken-down Ford Taurus to a wrecking yard in Pendleton, Oregon, shortly after Susan's disappearance, and had later ordered satellite images of the lot.

[39] On September 14, 2011, Utah authorities discovered a possible gravesite while searching Topaz Mountain, a desert area near Nephi, that Joshua had visited often as a campsite.

[41] On September 22, Steven was arrested on charges of voyeurism and child pornography after police found evidence that he had secretly videotaped young girls and numerous women, including Susan.

However, Manley also raised issues concerning the ongoing criminal investigations, Joshua's failure to admit normal personal shortcomings, his overbearing behavior with his sons and his persistent defensiveness and paranoia (attributed to the police and media attention in conjunction with underlying narcissistic traits).

[7] In the last week of January 2012, West Valley City police discovered about 400 images of simulated child pornography, bestiality and incest on a computer seized from the Powell residence.

[48] The images, while not illegal due to them being in a hand-drawn or cartoonish 3-D format, were cause for "great concern" to Manley, particularly given his earlier denial of possessing any such material.

Joshua was recommended to receive a more thorough psychosexual evaluation and polygraph test, but Manley suggested no change in the visitation schedule with the Powell children.

[7] Meanwhile, Joshua’s brother Michael established a Google Sites page that claimed Susan's parents were abusing and neglecting the children in collusion with child welfare authorities.

[49] On February 5, 2012, social worker Elizabeth Griffin Hall called 9-1-1 after taking Charlie and Braden to a supervised visit at Joshua's house in South Hill.

The official cause of death for Joshua and the two boys was determined to be carbon monoxide poisoning, though the coroner also noted that both children had significant chopping injuries on the head and neck.

[57] Records also showed that Joshua had withdrawn $7,000 from his bank account and had donated his children's toys and books to local charities the day before the incident.

On February 11, 2013, approximately one year after the death of Joshua and his sons, his brother Michael killed himself in Minneapolis by jumping from the roof of a parking garage.

[60] Jennifer Graves, Joshua's estranged sister, wrote a memoir with co-author Emily Clawson about the Powell family's tumultuous history.

In March 2015, Chuck Cox won a protracted court battle with Terrica and Alina Powell over control of Susan's estate.

Terrica and Alina had sought to have Susan declared legally dead to collect life insurance, but Cox ultimately gained full control of the estate.

[62] In 2019, an appeals court partially overturned that decision, ruling that the social workers did have immunity but that the question of DSHS's negligence could proceed to trial.

[65] Susan's family also pressured state lawmakers in Washington and Utah to pass bills that would restrict or block visitation rights for parents being investigated for murder.

[72] Dave Cawley, a reporter for KSL Newsradio in Salt Lake City, began a podcast on the Susan Powell case in November 2018.

The two-night special was touted to be the "definitive" account of the investigation, revealing Steven Powell's never-before-seen videos that were seized by police when he was arrested.

Gregg Olsen and Rebecca Morris covered the story in their book If I Can’t Have You: Susan Powell, Her Mysterious Disappearance, and the Murder of Her Children.