WASHINGTON - When Afghan security forces found an enormous cache of heroin hidden beneath concrete blocks in a tractor-trailer outside Kandahar in 2004, the local Afghan commander quickly impounded the truck and notified his boss.
Before long, the commander, Habibullah Jan, received a telephone call from Ahmed Wali Karzai, the brother of President Hamid Karzai, asking him to release the vehicle and the drugs, Jan later told American investigators, according to notes from the debriefing obtained by The New York Times. He said he complied after getting a phone call from an aide to President Karzai directing him to release the truck.
Two years later, American and Afghan counternarcotics forces stopped another truck, this time near Kabul, finding more than 110 pounds of heroin. Soon after the seizure, U.S. investigators told other American officials that they had discovered links between the drug shipment and a bodyguard believed to be an intermediary for Ahmed Wali Karzai, according to a participant in the briefing.
The assertions about the involvement of the president's brother in the incidents were never investigated, according to American and Afghan officials, even though allegations that he has benefited from narcotics trafficking have circulated widely in Afghanistan.
Both President Karzai and Ahmed Wali Karzai, now the chief of the Kandahar Provincial Council, the governing body for the region that includes Afghanistan's second-largest city, dismiss the allegations as politically motivated attacks by longtime foes.
"I am not a drug dealer; I never was, and I never will be," the president's brother said in a recent phone interview. "I am a victim of vicious politics."
But the assertions about him have deeply worried top American officials in Kabul and in Washington.
The U.S. officials fear that perceptions that the Afghan president might be protecting his brother are damaging his credibility and undermining efforts by the United States to buttress his government, which was been under siege from rivals and a Taliban insurgency fueled by drug money, several senior Bush administration officials said.
Their concerns have intensified as American troops have been deployed to the country in growing numbers.
"What appears to be a fairly common Afghan public perception of corruption inside their government is a tremendously corrosive element working against establishing long-term confidence in that government - a very serious matter," said Lt. Gen. David W. Barno, who was commander of coalition military forces in Afghanistan from 2003 to 2005 and is now retired. "That could be problematic strategically for the United States."
The White House says it believes that Ahmed Wali Karzai is involved in drug trafficking, and American officials have repeatedly warned President Karzai that his brother is a political liability, two senior Bush administration officials said in interviews last week.
Numerous reports link Ahmed Wali Karzai to the drug trade, according to current and former officials from the White House, the State Department and the U.S. Embassy in Afghanistan, who would speak only on condition of anonymity.
In meetings with President Karzai, including a 2006 session with the U.S. ambassador, the Central Intelligence Agency's station chief and their British counterparts, American officials have talked about the allegations in hopes that the president might move his brother out of the country, said several people who took part in or were briefed on the talks.
"We thought the concern expressed to Karzai might be enough to get him out of there," one official said.
But President Karzai has resisted, demanding clear-cut evidence of wrongdoing, several officials said. "We don't have the kind of hard, direct evidence that you could take to get a criminal indictment," a White House official said. "That allows Karzai to say, 'Where's your proof?' "
Neither the Drug Enforcement Administration, which conducts counternarcotics efforts in Afghanistan, nor the fledgling Afghan anti-drug agency has pursued investigations into the accusations against the president's brother.
Several American investigators said senior officials at the DEA and the office of the Director of National Intelligence complained to them that the White House favored a hands-off approach toward Ahmed Wali Karzai because of the political delicacy of the matter. But White House officials dispute that, instead citing limited DEA resources in Kandahar and southern Afghanistan and the absence of political will in the Afghan government to go after major drug suspects as the reasons for the lack of an inquiry.
"We invested considerable resources into building Afghan capability to conduct such investigations and consistently encouraged Karzai to take on the big fish and address widespread Afghan suspicions about the link between his brother and narcotics," said Meghan O'Sullivan, who was the coordinator for Afghanistan and Iraq at the National Security Council until last year.
Humayun Hamidzada, press secretary for President Karzai, denied that the president's brother was involved in drug trafficking or that the president had intervened to help him. "People have made allegations without proof," Hamidzada said.
Spokesmen for the Drug Enforcement Administration, the State Department and the Office of the Director of National Intelligence declined to comment.