Updated at 11:25 a.m. ET: KANDAHAR, Afghanistan -- Afghan President Hamid Karzai accused the Taliban on Monday of beheading 17 villagers, including two women, in volatile Helmand province, in a gruesome attack recalling the dark days of the hardline group's rule before their 2001 ouster. He ordered a full investigation into the "mass killing," which a local official said was punishment to revelers attending a party with music and mixed-sex dancing.   the Taliban denied they had taken part in the beheadings, which Karzai's office said took place in Kajaki district in the southern province.