It appears that the Pakistanis gave China a look (and feel) at the wrecked U.S. stealth helicopter left behind from the Osama bin Laden raid. Reports the New York Times:
American spy agencies have concluded that it is likely that Chinese engineers – at the invitation of Pakistani intelligence operatives – took detailed photographs of the severed tail of the Black Hawk helicopter equipped with classified technology designed to elude radar, the officials said. The members of the Navy Seals team who conducted the raid had tried to destroy the helicopter after it crashed at Bin Laden’s compound in Abbottabad, but the tail section of the aircraft remained largely intact.
We really didn’t need confirmation that Islamabad is, at best, a “frenemy” of America. But conduct doesn’t get much more hostile than this.