At midday on December 13, 2009, Koecher parked at the end of a cul-de-sac in the Anthem neighborhood of Henderson, Nevada, United States, and got out of his car, an action recorded on a nearby home's security camera.

After returning shortly afterwards, Koecher retrieved an unknown object from the vehicle and walked away, with another security camera capturing his reflection in a car window.

The reason for his trip to the Las Vegas area that day has never been determined; his family believes he was looking for work since he could not make the full rent payments on his apartment with the job he had.

Further investigation found credit card and cell phone receipts and witness statements showing that in the week prior to his disappearance, Koecher had been driving great distances around Utah and Nevada, including almost 1,100 miles (1,800 km) in one day.

The many temperature inversions in the Salt Lake City area that winter also bothered Koecher, so after a year he decided to leave his job at the Tribune and relocate to St. George, in the warmer southwestern portion of Utah.

He was able to find some work handing out flyers for a local window-washing firm, but this did not provide him with enough income to meet his expenses; by November 2009 he was several months behind on his rent.

[6] On December 10, 2009, Koecher apparently left St. George in the early morning hours and drove his Chevrolet Cavalier 300 miles (480 km) north on Interstate 15 to Salt Lake City, where he bought some gas with a debit card.

After two hours he left and decided to return to St. George the way he had come, stopping to buy gas again in Salt Lake City and Springville, followed by dinner at a Taco Time in Nephi.

[9] At 11:54 a.m., a home security camera on Savannah Springs Avenue in Sun City, a retirement community in the Anthem development in southern Henderson, recorded Koecher's car driving into the cul-de-sac where it was later found.

Six minutes later a figure dressed in a white shirt and slacks, believed by his family to be Koecher, walked the opposite direction down the sidewalk in front, carrying something in one hand that appeared to be a file folder or portfolio.

Around 5 p.m. that day it pinged a tower at the intersection of Arroyo Grande Boulevard and American Pacific Drive, more than 10 miles (16 km) northeast of where he had parked.

[2] A day after that last ping, Sun City's homeowners' association took note of the car at the end of the Savannah Springs cul-de-sac and tried to find its owner.

At one point, when employees at an International House of Pancakes told them that a man fitting Koecher's description had eaten there for three weeks straight, they themselves ate there for four nights.

[10] In April 2010, another party of searchers scoured the open desert south of the Henderson Executive Airport to the west of where Koecher had parked in response to a tip passed along to a former LVMPD officer working as a private investigator for the family.

[15] Rolf had, with his wife and family, recently finished filming an episode of the Investigation Discovery cable channel's documentary series Disappeared about Steven's case.

[7] Members of the WebSleuths Internet forum also took up the case; they assembled a timeline of events based on newspaper accounts and social media posts by Koecher's family and friends.

[2] In 2015, a local search and rescue group organized another effort, this time going high up the hills south of Anthem, on a different theory of what Koecher might have been doing.

[2] Despite the odd location where he parked his car, on the security video Koecher is neatly dressed and walking purposefully, which his family believes was an indication he was at the scene intentionally.

His father said that the car was in working order and the gas tank was half full when he found it on December 17, after his wife was contacted by the Sun City homeowners' association.

[11] In the car were the Christmas presents Steven had bought for his brother and his family at Kmart the previous day, as well as job applications and the flyers from his employer that had helped the homeowners' association find his parents.

[9] Koecher's unusual, and mostly unexplained, travel in the days leading up to his disappearance has led to suppositions that he may have turned to some sort of illicit activity for income.

[12] Another vehicle seen on the security camera footage driving up and down the street around the time Koecher parked and walked away from his car was investigated, and turned out to be a local real estate agent showing a house in the area.

Koecher kept a diary, but recorded no problems in his life at the time of his disappearance beyond his monetary issues and his ongoing bachelorhood, neither of which he believed would last much longer.

Police officers who came to investigate the next morning forced entry into the house and found two box fans blowing at a wet spot on the couch.

[20] Steven Powell, Joshua's father, outlined the theory in a February letter to police and FBI agents investigating his daughter-in-law's case.

[22] Joshua's father Steven, who had been convicted of child pornography and voyeurism after, among other things, explicit pictures he had secretly taken of Susan were found on his computer, died in 2018, a year after finishing his prison sentence.