The Muslim aid charity Al-Fatiha Global has declined to comment on media reports that Alan Henning, a British aid worker kidnapped in Syria, travelled to the country on an aid convoy with which it had been involved.
Various media outlets have reported that Henning, 47, of Greater Manchester, took part in an overland aid convoy delivering supplies to refugees on the Syrian-Turkish border last year, and was kidnapped shortly after crossing into Syria at the end of last year.
The Islamic extremist group IS threatened to kill Henning in a video released on 13 September. The UK government has said it cannot attempt to rescue him because it does not know where he is.
Henning drove to the area with an aid convoy variously reported as having been organised by Al-Fatiha Global or by the fundraising group Rochdale Aid 4 Syria, which raises money for Al-Fatiha and other charities.
A spokeswoman for Al-Fatiha said the charity had no comment to make on the reports.
The charity has been the subject of a statutory inquiry by the Charity Commission since April, over management and financial issues and concerns raised after a volunteer was allegedly pictured with masked gunmen in Syria in March.
An appeal to the charity tribunal by one of the charity's trustees against the opening of the inquiry will be heard later this year.
The video depicting Henning also showed the killing of another Briton, David Haines, who had been working for the Paris-based aid agency Acted.
A statement posted on the Acted website said Haines had been working as a humanitarian since 1999 and had worked in conflict areas including Africa, the Balkans and the Middle East. He was kidnapped in March 2013.
"The horrible assassination of David, an aid worker, goes against all humanitarian principles and is a crime against humanity," the statement said. "It will not detract us from our commitment to alleviate populations' suffering. The perpetrators of this barbaric crime should be brought to justice."