Powell called in sick to his former Washington state job on Dec. 8 and 9 of 2009, state officials said.
His absence from work coincides with the days when his son, Josh Powell, rented a car in Utah and traveled some 800 miles before returning it.
Josh Powell himself missed work on Dec. 7 after having gone camping with his boys, then 2 and 4, the night before in freezing temperatures. The man later said he had mistakenly thought the day was Sunday (instead of Monday), and added he knew nothing about his wife's whereabouts, only that she should have been at work. The man said he had last seen his wife before leaving for the camping trip.
Investigators later found Susan Cox Powell's cellphone in the center console of Josh Powell's car, according to a search warrant unsealed last week. The phone did not contain a sim card, detectives said, and Josh Powell said he did not know why the phone was in his car. Susan Cox Powell's purse, which contained her ID and credit cards, was found, undisturbed, in the bedroom of their home.
Last year, authorities searched Steve Powell's home, computer and cars for evidence in Susan Cox Powell's disappearance - and instead said they found thousands of voyeuristic pictures and videos, including those of the missing woman. They also found child pornography recorded by Steve Powell.
Steven Powell has admitted to having had a "romantic obsession" with his daughter-in-law, and said he wrote love songs about her before she vanished.
"There were definitely some things that were probably inappropriate for a married woman and her father-in-law. I acknowledge that," he said, adding it was Susan Cox Powell who had initiated the flirtatious relationship between them.
Steven Powell also said his daughter-in-law became upset when his advances toward her became increasingly overt.
"When I took liberties or whatever, she became very upset and accused me of hitting on her," he said.
But the missing woman's father, Chuck Cox, said his daughter claimed years ago that "something had happened" with Steven Powell that made her uncomfortable. He said she didn't disclose the details.
"She said something about Steve had wanted her to be a common wife for him and Josh," Chuck Cox said. According to him, when his daughter discussed the remark with Josh Powell, he dismissed it as part of his father's penchant for saying outrageous things.
Chuck Cox said he believes his daughter's discomfort with her father-in-law was part of what motivated her to move her family to Utah from Washington.
"She wanted as far away from him as possible," Cox said.
Steven Powell has denied the claim that he and his son wanted to share Susan Cox Powell as a wife.
Investigators in Utah uncovered incestuous sex images on Josh Powell's computer. The images were disconcerting enough that they prompted a psychologist to recommend that Josh Powell undergo an intensive psycho-sexual evaluation.
When police first entered the Utah home after Susan Cox Powell was reported missing, two fans were setup to blow air on the sofa. Josh Powell, told investigators he had just cleaned the sofa at his wife's request. Detectives found traces of the missing woman's blood on the tile floor near the sofa.
An acquaintance of Josh Powell told police he often talked about how he liked to go camping in the west desert of Utah. The area is "so full of mine shafts, tunnels that are very unstable so you could dispose of someone and no one would ever search for the body," the document said.
Investigators have searched parts of the west desert, and have not found any sign of the missing woman. Josh Powell was the only suspect in her presumed murder, but maintained his innocence.
After his wife's disappearance, Josh Powell invoked power of attorney and emptied Susan Cox Powell's IRA accounts. He also moved with the boys to his father's home in Puyallup, Wash., but Steve Powell was arrested and charged with voyeurism and child pornography last September. The boys were placed with Susan Powell's parents for their safety.
On Feb. 5 - a few days after incestuous images found on his computer prompted a judge to order him to undergo a psycho-sexual evaluation - Josh Powell locked a social worker out of his rental house, attacked the boys with a hatchet and then ignited the home in an explosive, gas-fueled inferno. The social worker was not injured.
In 2011, Steven Powell pleaded not guilty to 14 counts of voyeurism and one count of child pornography.