The opium was detected last month during an anti-drug-trafficking operation in the southern province of Kandahar, German news magazine stern reports.
British troops arrested a group of Taliban and an Afghan police officer who had cooperated with them. Those arrests led investigators to a farm owned by Ahmed Wali Karzai, head of the provincial council of Kandahar and half brother of President Hamid Karzai. In a walled compound on the farm, troops found several tons of raw opium, stern says in the report published Thursday.
The magazine writes the president has had access to transcripts and videos of the investigation, but did not react. Karzai's government record has been stained by allegations of corruption and connections to the drug business; much had pointed to his half brother's involvement in the drug business, a charge Ahmed Wali has always denied.
The report comes as Washington is shifting its strategy in the fight against Afghanistan's narcotics industry. After focusing mainly on destroying poppy fields, U.S. forces are now hunting down the criminals across the entire drug-trafficking value chain.