`:Grendel dies of the shock from Beowulf tearing his arm off.  When Beowulf finds him in the lair, he is already dead; Beowulf only cuts his head off so he can take it back to Heorot as a trophy, to replace Grendel's arm, which Grendel's mother took away with her when she seized the Dane AEschere.  When Beowulf finds Grendel (lines 1585-90) he is licgan aldorleasne, ``lying life-less.``  Also, at line 1257, the poet says that Grendel's avenger (his mother) lifde aefter him, so clearly Grendel is already dead by the time Grendel's mother attacks Heorot.    `