SALT LAKE CITY >> The latest batch of documents released in the Susan Powell case show investigators seeking permission to mount wiretaps on her husband Josh Powell’s phone after she vanished in December 2009.

Those were among the new details to emerge in hundreds of pages of search warrants released Friday that were part of the investigation into the West Valley City woman’s disappearance.

The warrants add to the thousands of documents that became public Monday when police ended their investigation into her disappearance.

The records released earlier this week show that Utah officials believe Josh Powell likely killed his wife, and that his brother, Michael Powell, helped dispose of the body, but authorities felt they didn’t have enough evidence to prove that theory in court. No trace of Susan Powell has been found.

Last year, as the investigation continued, Josh Powell killed himself and his two young sons in an explosive house fire. Michael later jumped to his death from a parking garage in Minnesota.

The Salt Lake Tribune reports that among the warrants released Friday, one 65-page document aimed to get permission to wiretap phones belonging to Powell and his father, Steve Powell. The warrant also describes Steve Powell as "instrumental in the obstruction" of the investigation. But police have said that they do not believe he was directly involved in her disappearance.

Police believe that Josh and Steve Powell would discuss their alleged crimes on the phone, and hoped to gather information by listening in.

A later warrant recounts some of the information gathered via wiretapping. While they were searching for the body of Susan Powell near Ely, Nev., police heard Josh Powell over the wiretap saying that her body would not be found there.

Yet another warrant mentions that during an interview, one of the couple’s sons said Susan went camping with them but did not come back "and he did not know why." Several days later, when the boy was at church in Washington, he told a Sunday school teacher that "my mom is dead," the warrant states.

Other details to emerge in the search warrants include that police toyed with the idea of sending an undercover female officer to "initiate an acquaintance relationship" with Josh Powell. And a grand jury also was ruled out because investigators didn’t believe it would produce more information.