The father of British man Nasser Muthana said one of the unmasked Isis killers featured in the latest propaganda film showing the beheading of an American aid worker "looks like" his son.
Peter Kassig, known as Abdul-Rahman, was taken hostage in Syria in October 2013. Distressing video footage showing his apparent death appeared on social media over the weekend. His family said they are heartbroken to learn the news of his death.
Nasser Muthana, 20, from Cardiff featured on a Islamic State video last summer. He features as part of a line-up of fighters in the latest beheading video, but is not shown killing Kassig.
Speaking to the Daily Mail, Nasser's father said:
I cannot be certain but it looks like my son. He must be mentally ill - either that or there is something else not right.
Mr Muthana's other son Aseel is also thought to be in Syria.
Tonight on ITV former Wales rugby captain Eddie Butler undertakes a personal TV journey to discover the stories of thirteen Welsh Internationals killed on the battlefields of Western Europe during the Great War.
In Rugby At War, a special co-production between ITV Wales and the Welsh Rugby Union commemorating the centenary of the start of the conflict, Eddie pays tribute to the pivotal roles undertaken by this band of fallen Welsh rugby players. They came from diverse backgrounds, from across Wales, but all were united by their love of the game and their courage in the face of war.
The most famous of the group was former Wales rugby skipper Captain Johnnie Williams, who scored an incredible 17 tries in 17 games. He died at Mametz Wood, one of the bloodiest and most devastating battles of the First World War where Welsh casualties alone numbered some 4,000.
Eddie travels to the now peaceful French countryside to see for himself where his predecessor rugby Welsh captain fell, and searches for his grave among the vast sea of white headstones in the Corbie Communal Cemetery.
Rugby at War, Tonight on ITV Cymru Wales at 7.30pm
People in Aberystwyth have paid tribute to the servicemen who have died in conflict since the start of the First World War 100-years-ago.
Tributes will be paid today to the millions of British servicemen and women who have died since the First World War began 100 years ago.Read the full story ›
Events will be held across Wales today to mark the centenary of the outbreak of the First World War.
The Senedd will fall silent at 11:00am and the last post will be sounded to mark the ultimate sacrifice made by Welsh soldiers.
In the year that we mark the centenary of the outbreak of the First World War it is right that the National Assembly takes a central role in marking the sacrifice of soldiers who have made the ultimate sacrifice.
More than 40,000 Welsh soldiers gave their lives in the First World War, with thousands more killed in conflicts across the globe and throughout history.
Many of us have a personal link to the brave men who made the ultimate sacrifice on the battlefields.
In Cardiff, the First Minister was among those who laid poppy wreaths at the Cenotaph.Read the full story ›
The village of Colwinston in the Vale of Glamorgan has unveiled a memorial to four of its men who died in the Second World War.
Colwinston is one of only three 'Thankful' villages in Wales - places that saw all of its men who served in First World War return home.
Carwyn Jones has spoken of a "debt of gratitude" owed to members of the armed forces who have given their lives.
The First Minister was speaking ahead of the Welsh National Service of Remembrance which is taking place in Cardiff today.
Members of the Royal Navy, the Army, the Royal Air Force and other detachments have met in Cathays Park in Cardiff this morning to mark their respects.
"The Welsh National Service of Remembrance provides us with an opportunity to pay our respects to those who have lost their lives in conflict. It's a great honour, especially as we mark 100 years since the outbreak of the First World War, to be able to pay tribute to those armed forces personnel who have given their lives. We owe them a great debt of gratitude."
Wales' national observance of Remembrance Sunday is underway in Cardiff today.
Detachments from the Royal Navy, the Army, the Royal Air Force, the Army's University Officer Training Corps and the Merchant Navy and Fishing Fleets have been marching to the Welsh National War Memorial in Cathays Park to form up around the memorial.
Those detachments will be joined by columns of ex-Servicemen and women, organised by the Royal British Legion and columns of civilians representing organisations connected with current and past conflicts.
"The annual Welsh National Service of Remembrance has added resonance this year as we mark 100 years since the outbreak of the First World War. It is important that we remember and reflect on the sacrifice made by men and women in conflict and the service gives an opportunity for Cardiff and Wales to pay its respect to all those who fought and died in two World Wars and in all conflicts around the world to secure the peace and freedom that we enjoy today."