American female hostage ISIS
ISIS claimed that American aid worker Kayla Mueller was killed in a Jordanian airstrike in Raqqa.Twitter

American aid-worker Kayla Mueller, whom the US government this week declared as dead in Syria, was nearly rescued from the Islamic State militant's capture, when a man posing as her "husband" turned up at the place where she was held, only to be sent away moments later.

According to Arizona Rep. Paul Gosar, who gathered information from the 26-year-old's family members, a man posing as Mueller's husband demanded her release from ISIS but remained unsuccessful at the attempt after Mueller, unaware of the rescue attempt, told the ISIS militants that she was unmarried, Fox News reports.

The person who posed to be the husband, most likely, was the Syrian man who was captured along with Mueller in August 2013, a spokesperson for Gosar Steven Smith was cited as saying. The unnamed man was released by the Sunni hardliner group days later while the 26-year-old Mueller was transported to another cell.

The man, calling himself Mueller's husband, turned up suddenly at the Syrian terrorist camp where she was held hoping that he could somehow convince the terrorist organisation to release her. But Mueller "had no information" that a rescue operation was underway and all that the members of the outfit needed to do was to confirm from Mueller whether she was married or not. 

"She said she didn't have a husband" Smith was quoted as saying adding that it was all that the captors needed, in order to send the man away from the place.

Meanwhile, reports on Wednesday suggested that Mueller was later possibly married off to one of the commanders of the jihadist group during her captivity, according to officials.

Intelligence gathered using techniques such as eavesdropping on ISIS members who referred to her during phone conversations, and tracking fighters guarding a sensitive site hinted that she was with her 'ISIS keeper' most of the time, two officials were cited as saying.

Obama confirmed the aid-worker's death this week although there are no official details on how or when she died. ISIS had announced last Friday that the aid worker was killed in a Jordanian airstrike in northern Syria. The strike allegedly hit an ISIS hideout where she was being held.