Steven Sotloff’s apparent beheading came less than a week after his mother made an emotional appeal for the Islamic State (Isis) to “follow the example set by the Prophet Mohamed” and show mercy.
Shirley Sotloff addressed the leader of the Sunni militants directly in the short message, respectfully using his full name, Abu Bakr al-Baghdadi al-Quraishi al-Hussaini, and his self-bestowed title of “caliph of the Islamic State”.
Begging his captors not to punish her son for the actions of the American Government, she said the 31-year-old travelled to Syria to cover the “suffering of Muslims at the hands of tyrants”.
Mr Sotloff was a freelancer who had contributed to magazines including Time, The Christian Science Monitor and Foreign Policy, reporting from conflict zones across the Middle East and North Africa before he was abducted near Aleppo in August 2013.
“Steven is a loyal and generous son, brother and grandson,” Mrs Sotloff said.
“He is an honourable man and has always tried to help the weak.
“We have not seen Steven more than a year and we miss him very much.
“We want to see him home safe and sound and to hug him.”
The family had not broken a media black-out since Mr Sotloff was abducted for fear it would put him in further danger and the message was the first public statement made.
It came after the journalist was paraded in front of cameras in a video of the beheading of another US journalist, James Foley, and Isis threatened to kill him next if Barack Obama did not stop air strikes against the group in Iraq.
The President stepped up the bombing campaign days later, despite a petition signed by more than 11,500 people asking him to “do everything possible” to free Mr Sotloff.
At the time, a spokesman for the White House said the administration was “deeply engaged” in trying to gain the release of all Americans held hostage in the Middle East.
American special forces attempted to free Mr Sotloff and Mr Foley along with other hostages in a secret operation in July but failed their mission because they had recently been moved from the oil refinery in northern Syria targeted.
Isis is violently enforcing its version of Sunni law with the aim of establishing an Islamic state through Iraq, Syria and beyond but Mrs Sotloff urged them to use different teachings from the Koran.
“Since Stephen's capture, I've learned a lot about Islam,” she said.
“I've learned that Islam teaches that no individual should be held responsible for the sins of others.
"Stephen has no control over the actions of the US government. He's an innocent journalist.”
In pictures: Steven Sotloff
In pictures: Steven Sotloff
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Steven Sotloff inside Al-Fateh Mosque in Manama, Bahrain, in 2010
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Journalist Steven Sotloff, left, pictured in Libya in 2011
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Steven Sotloff pictured in 2010 near Lulu Roundabout in Manama, which later became the iconic center for the 2011 pro-reform protests in Bahrain
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Journalist Steven Sotloff pictured in Egypt
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Media gather outside Steven Sotloff's family home in Pinecrest, Florida
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Shirley Sotloff during a recent appeal to the captors of her son
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Pinecrest police officers are positioned at the home of Arthur B. Sotloff and Shirley Sotloff, the parents of American freelance journalist Steven Sotloff, in Pinecrest, Florida
Asking al-Baghdadi to use his power to grant amnesty, she added: “I ask you to please release my child.
“As a mother I ask your justice to be merciful and not to punish my son for matters he has no control over.
“I ask you to use your authority to spare his life and to follow the example set by the Prophet Mohamed, who protected people of the book.
"I want what every mother wants - to live to see her children's children. I plead with you to grant me this."
The video of Mr Sotloff’s apparent beheading emerged on Tuesday evening but has not yet been verified.
A spokesperson for his family said they are “grieving privately” and will not be making a public statement.