From the [1] SITE Institute, with thanks to the Constantinopolitan Irredentist:

A message was recently posted on a jihadist forum discussing the acceptability of beheadings in jihad. Ultimately, the author sanctioned them as valid, in accordance with the beliefs of Muhammad....he refers to past precedents of executions in history, arguing that these examples in history "prove that killing people and slaughtering them is a Sunnah [an accepted Islamic practice]."