A funeral for Kurds killed by Turkish-led forces in Syria this month after President Trump pulled American troops out of the way. The move left the Kurds feeling betrayed.
Credit…Delil Souleiman/Agence France-Presse — Getty

QAMISHLI, Syria — When the international manhunt for Abu Bakr al-Baghdadi, the leader of the Islamic State, zoomed in on a village in northwestern Syria, the United States turned to its local allies to help track the world’s most-wanted terrorist.

The American allies, a Kurdish-led force that had partnered with the United States to fight ISIS, sent spies to watch his isolated villa. To confirm it was him, they stole a pair of Mr. al-Baghdadi’s underwear — long, white boxers — and obtained a blood sample, both for DNA testing, the force’s commander, Mazlum Abdi, said in a phone interview on Monday.

American officials would not discuss the specific intelligence provided by the Kurds, but said that their role in finding Mr. al-Baghdadi was essential — more so than all other […]