Powell Family Tragedy Timeline The explosion at the Washington home of Josh Powell that killed him and his two sons brought a tragic end for a family whose last two years were surrounded in mystery and conflict after wife and mom Susan Powell was reported missing by her husband. Police in Graham, Wash. said Sunday that the explosion, which is believed to have been caused by a gas leak, was intentionally ignited by Powell. A Child Protective Services worker had just dropped off Powell's two sons Braden, 5, and Charles, 7, at the house for a supervised visit. When they arrived Powell brought the boys inside and quickly locked the door. Seconds later the house exploded. Susan Powell was last seen on Dec. 6, 2009. Since she disappeared, a series of escalating events involving Josh Powell, his father Steve Powell and Susan Powell's parents Chuck and Judy Cox led to Sunday's tragic murder/suicide. Weekend of Dec, 6-7, 2009: Susan Powell, then 28, is last seen at the West Valley City, Utah, home she shared with her husband and their two young sons. Josh Powell told authorities that he had decided take an impromptu midnight camping trip the boys -- in the midst of a blizzard -- the night his wife vanished. Powell says that he returned home to find his wife gone; that Monday she did not show up to her job at Wells Fargo Financial. Dec. 24, 2009: After two weeks of investigations that involved searches of the Powell's home and interviews with the two boys -- who confirmed the camping trip they'd taken with their father -- police name Josh Powell a "person of interest" in his wife's disappearance. While searching the house, investigators found two fans drying a wet area on the rug, where a red stain had been removed. Josh Powell said that his wife had been cleaning the rug before she disappeared. His father Steven Powell publicly theorizes that Susan had skipped town with a man from St. George, Utah, who also disappeared from a Christmas party abruptly the same night she vanished. November 2010: In an interview with the Salt Lake Tribune, Josh Powell says that he blames Susan's family for causing her to leave under pressure. "She knows she will be chewed up like hamburger when she comes back," Powell said. She can't come back with them treating her this way â¦ They want her to be perfect, a saint with no fallibility. January 2010: Josh Powell moves with his two sons to Puyallup, Wash. -- the town where both he and Susan grew up -- where he lived in a house with his father. Josh Powell maintained that his wife left on her own; during the investigation he described his wife as "extremely unstable" and claims her mental illness led to her disappearance. Aug. 18, 2011: A possible break in the case leads investigators to search abandoned mine shafts near Ely, Nev., which is more than 200 miles southwest of the family's home in of West Valley -- but no remains are found. Aug. 20, 2011: Steven Powell and Susan's father Chuck Cox get into a shouting match at a Puyallup, Wash. remembrance rally for Susan. Steve Powell confronts Chuck Cox at the rally, calling him a "liar" and a "cyber bully." Speaking with the local media, Josh Powell says he does not appreciate the rally being near his home. "Putting this in my neighborhood is not appropriate," Powell said. They're trying to push an agenda. ... I don't know what happened to her. There are 1,000 different theories that people need to consider in strong and serious ways. Aug. 25, 2011: Investigators and forensic specialists comb the home that Powell shared with his father and his two boys. Police say that they removed at least three computers and four boxes of material from the home. Meanwhile, Steven Powell says that he plans to post his daughter-in-law's teenage journals on the website SusanPowell.org; he reportedly says that the journals show that his daughter-in-law is capable of walking out on her husband and their two sons. In an interview with "Good Morning America" Steven Powell makes new claims that he had a flirtatious relationship with his daughter-in-law that was "a little beyond the pale." "Father-in-law - daughter-in-law flirting with each other, maybe some sexual touching or whatever," Steven Powell said of the relationship that he developed with his son's wife, adding that he started to fall in love with her, and stated, "there's no question in my mind that the feelings were mutual." 14, 2011: Utah authorities find a shallow grave in the mountains of Utah, which they believed might contain the remains of Powell. However no bones, tissue or definitive evidence related to Powell was found in the grave site, which was near Topaz Mountain -- 30 miles south of where Josh said he took the boys camping the night Susan disappeared. 22, 2011: Steven Powell is charged with using a telephoto lens to take photos of two young girls in the bathroom of a neighboring house. The photos, which were found during the August search of his home, are among thousands he secretly took of women's buttocks and breasts, according to charges filed against him. Powell was charged with 14 counts of voyeurism and one count of child pornography and held on $200,000 bail. Josh Powell is named a "subject" in the child porn investigation, according to assistant Attorney General for Washington John Long. Susan Powell's parents file to gain custody of the two boys in court the following day. Sep. 23, 2011: A judge issues a permanent injunction that forbids the Powell men from publishing any material from Susan Powell's journals. 28, 2011: Josh and Susan Powell's two boys are ordered by a Washington court to remain in the custody of her parents Chuck and Judy Cox, because they had been living in a dangerous home environment with sexually explicit material, and because of the possibility that Josh Powell participated in the voyeurism and child pornography charges against his father. He is, however, granted visitation rights with his boys. Feb. 1, 2012: A judge rules that the two boys are to remain with their grandparents, the Coxes, while Josh Powell is ordered to take a psychosexual evaluation and polygraph test in order to get his boys back. Police noted that information and images were found on Josh Powell's computer that "specifically related to their children's welfare." In an affidavit to the court, Josh Powell pled his case that his boys should be with their father. For over four months already, my interactions with my sons and many other aspects of my character have been investigated and documented â¦ I have proven myself as a fit and loving father who provides a stable home even in the face of great adversity. ... It is time for my sons to come home. Feb. 5, 2012. Josh Powell sets off an explosion at his Washington home today that killed himself and his two sons. "I'm sorry, goodbye," Powell wrote in an email to his attorney.