Mullah Baradar is the Taliban number 2, and was arrested by the Pakistani ISI in January. It was a bizarre episode, because Mullah Baradar was the reported lynchpin in Karzai's efforts to secure a peace deal with Taliban. Well, check out the indispensable Ahmed Rashid for this tidbit on Baradar's arrest:

When Karzai visited Islamabad on March 10 to find out why his interlocutor Mullah Baradar was arrested, he was, according to Afghan officials, bluntly told by Pakistan's generals that the Americans are bound to leave and that if he wanted Pakistani help resolving issues with the Taliban, he would first have to close Indian consulates in Kandahar and Jalalabad. Pakistani officials deny threatening Karzai and insist that they want a peaceful and stable Afghanistan once the Americans leave. But other sources have confirmed that such ultimatums were delivered.

The ISI playing hardball? Couldn't be...