The family of Margaret Hassan, a high profile aid worker abducted in Iraq last month, says they believe "that Margaret is probably gone."

Hassan, 59, was the director of CARE International operations in Iraq. She spent close to three decades working as an aid worker in Iraq, and is married to an Iraqi citizen. She shares Irish, British and Iraqi citizenship.

"We had kept hoping for as long as we could, but we now have to accept that Margaret has probably gone, and at last her suffering has ended," said a statement from Hassan's four brothers and sisters.

"Those who are guilty of this atrocious act, and those who support them, have no excuses.''

The statement, released by the British Foreign Office, did not say why the family believed Hassan had died.

Jihad Ballout, a spokesman for the Al-Jazeera TV network, told The Associated Press they received a videotape a few days ago. It shows a militant firing a pistol into the head of a blindfolded woman wearing an orange jumpsuit. "She was presumed to be Mrs. Hassan,'' Ballout told The Associated Press.

The network was planning to show British officials the videotape. But Al Jazeera later told Reuters they would not be airing the video to the public.

British Foreign Secretary Jack Straw said that based on their experts' examination of the video, "we have today had to inform Margaret Hassan's family that, sadly, we now believe that she has probably been murdered, although we cannot conclude this with complete certainty.''

"To kidnap and kill anyone is inexcusable. But it is repugnant to commit such a crime against a woman who has spent most of her life working for the good of the people of Iraq,'' Straw said.

Hassan's husband, Tahsin, urged the kidnappers to return her body for burial, if she is indeed dead.

CARE expressed its shock and sadness at the news.

"It is with profound sadness that we have learnt of the existence of a video in which it appears that our colleague Margaret Hassan has been killed," the agency said a statement. "We are shocked and appalled that this has been the apparent outcome of her abduction."

 "Mrs. Hassan was an extraordinary woman who dedicated her life to the poor and disadvantaged in Iraq, particularly the children. The whole of CARE is in mourning."

If her death is confirmed, Hassan would be the first woman to be killed by her kidnappers. Other women have been taken hostage, but were later released.

Hassan was kidnapped on Oct. 19 in Baghdad on her way to work. Gunmen surrounded her car, pulled the driver and her companion out, and drove off with her in the vehicle

In early November, the unknown group holding her demanded that Britain withdraw its troops from Iraq within 48 hours. It said that if that did not happen, it would hand Hassan over to the al Qaeda group in Iraq, headed by Jordanian militant Abu Musab al-Zarqawi.

The group led by al-Zarqawi has been blamed for a number of beheadings including three Americans and a Briton.

Shortly after the kidnapping, CARE International withdrew its staff from Iraq. The aid agency had been in Iraq since 1991, and was one of the few humanitarian groups to remain despite a recent spike of violence against U.S. soldiers and foreign workers.