It is quite possible the American aid worker and hostage Kayla Mueller was offered as a bride to an Islamic State militant during her captivity, CNN revealed.

United States Intelligence officials, who have chosen to remain anonymous during the interview said that Mueller was either coerced, sold or forced into the pairing.

The National Security Council added that it was breaking protocol to provide information about an American hostage, but the U.S. government said that all statements made now remain to be speculations.

"Reports that have been published by certain news outlets regarding Kayla's time in (ISIS) captivity are speculative and unproven at this time," spokeswoman Bernadette Meehan said. "The U.S. government continues to analyze any information regarding Kayla's captivity but has not corroborated any of the multiple theories regarding the conditions throughout the duration of her captivity."

Mueller's parents announced on Tuesday that their daughter, who was captured in northern Syria back in 2013, had passed away. ISIS sent the family a private message over the weekend with information about her death, including photos.

The first picture showed Mueller wrapped in a burial shroud, with some hits and bruises on her faces.

ISIS said that Mueller died due to a Jordanian airstrike on Raqqa, which collapsed a building Mueller was in.

Her family went on air and talked about Mueller. "She had a quiet, calming presence. She was a free spirit, always standing up for those who were suffering and wanting to be their voice. Kayla's calling was to help those who were suffering, whether in her home in Prescott, or on the other side of the world," her aunts, Lori Lyon and Terri Crippes said.

She was always so selfless, eager to help out those in need. After graduating in 2009 from the Northern Arizona University, she began working with humanitarian groups in northern India, Israel and Palestinian territories.

While in Aleppo, Syria, Mueller was captured by ISIS after she was leaving a Doctors Without Borders hospital. ISIS contacted her family in May with proof of her life, and demanded a $7 million ransom by August 13, otherwise Mueller will be killed.

At one point, ISIS even suggested that they trade Mueller for Dr. Aafia Siddiqui, a prisoner being held in Texas who was convicted for conspiring with the enemy. Later, they demanded the release of Siddiqui, also known as "Lady Al Qaeda."

But all negotiations made to save Mueller failed.

Her friend Orouba Barakat even shared short audio clip made by Mueller right after she was kidnapped, and she was begging for help. "Please try to help me, get me out of here. I'm so sick, I'm dying," Mueller said in the video.

Barakat, a Syrian journalist attempted several times after to contact Mueller via Skype or e-mail, but she never heard back from her friend since then.

Moreover, U.S. President Barack Obama defended their actions, saying they used every means possible to help free the hostages.

"We devoted enormous resources, always devote enormous resources to freeing captives or hostages anywhere in the world. And I deployed an entire operation - at significant risk - to rescue not only her but the other individuals who had been held, and probably missed them by a day or two, precisely because we had that commitment," Obama said.