This image taken from video from Shaam News Network, which has been authenticated… (Shaam News Network, Associated…)
WASHINGTON — The hunt for proof that Syrian government forces used banned chemical weapons may come down to a rotting corpse exhumed late last month from a makeshift cemetery near Damascus.
The grave diggers — a Syrian doctor and several medical students — were seeking tissue from the remains of a man who had died of respiratory failure after a rocket allegedly spewed poison gas on Dariya, a suburb of the Syrian capital, on April 25.
Reaching the cadaver several feet down, the team sliced open the cloth shroud, cut into the torso and removed a small piece of lung. They also took an eyeball, a lock of hair and bits of clothing, according to two fellow Syrian opposition activists who helped arrange the graveside dissection.
It was more than a week before the samples — sealed in small plastic containers and initially kept on ice — were slipped out of Syria by opposition operatives and handed to officials at the U.S. Embassy in Beirut for testing.
The macabre story shows how hard the Syrian opposition is working to prove its contention that President Bashar Assad's government has used poison gas against rebels. President Obama warned Syria last year that use of lethal chemical agents or their transfer to terrorists would cross a "red line" and prompt a still-unspecified U.S. response.
The episode also helps explain why the Obama administration is concerned about the "chain of custody" of samples emerging from Syria, worried that chemical-laced tissue, soil and other materials may have been faked, contaminated or spoiled by heat and time.
Last month, the White House acknowledged in a letter to Congress, even before the corpse in Dariya was exhumed, that it had received "physiological samples" that led U.S. intelligence agencies to conclude "with varying degrees of confidence" that Assad had used sarin nerve gas "on a small scale." It did not say how the samples were obtained.
The Dariya graveyard mission was organized by the Syrian Support Group, an exile organization with offices in Turkey and Washington. It has implored the United States and its allies to intervene in the two-year Syrian civil war, and opposition activists hope that providing proof of illicit weapons use may be enough to force a reluctant international community to act.
"We and the people on the ground are ready to do anything, including digging up graves, in order for the world to know the truth about these attacks, so they will change their stance," said one of the activists, who requested anonymity to protect their safety.
On Friday, the Syrian Support Group and other opposition forces publicized new reports alleging that Assad's forces the night before had used poison gas in Adra, on the outskirts of Damascus.
One group, citing sources in Syria, said in a statement that the attack killed four people and sickened 50, "some with suffocation and others with fatigue accompanied by a severe allergic reaction." The report, and previous reports like it, could not be confirmed.
The fog of war seems especially dense when it comes to determining whether illicit chemical attacks have occurred in Syria — and if so, which side was responsible.
Experts say it's possible that some combatants have used tear gas or other crowd-control agents that are not banned. It's also possible that government or insurgent forces have shelled pesticide or chemical factories and accidentally released clouds of lethal or incapacitating toxic mist.
They note that none of the alleged attacks have produced mass casualties consistent with a major nerve or mustard gas attack.
Robert Serry, the United Nations Middle East peace envoy, warned the U.N. Security Council this month of "mounting reports on the use of chemical weapons" in Syria. He called on Assad to allow a team of U.N. inspectors into the country to investigate the allegations.
The U.S. so far has provided humanitarian and other nonmilitary aid to the rebels, resisting calls to get more directly involved in a conflict that U.N. officials say has killed more than 80,000 people.
American confidence about chemical warfare evidence varies because the "chain of custody is not clear," said Bernadette Meehan, a spokeswoman for the White House National Security Council. "That is why we are working with the Syrian opposition, friends and allies to share and evaluate information associated with reports of the use of chemical weapons."
The Dariya operation was the Syrian Support Group's second attempt to put evidence into the hands of a foreign government.
In March, it enlisted supporters to collect hair and urine samples from victims, plus soil and other material, after an alleged chemical attack killed 25 people and wounded dozens in Khan al Asal, near the northern city of Aleppo.
The samples were smuggled across the border to Turkey and handed to a British government representative, according to the two Syrians who also described the Dariya incident.