A sack containing human remains was on Wednesday recovered from the grave found at a village in the former stronghold of Trinamool Congress-backed Bhumi Ucched Pratirodh Committee in Nandigram.As the grave was dug up, part of the sack inside gave way and revealed portions of a human skull, Block Development Officer of Nandigram-I Santiram Gorai, who permitted the grave to be opened and was present at the site, said.Work was on to bring up the sack, he said.The grave was discovered by the villagers on December 10 after it cracked open and a foul smell came from it.Villagers, police and the CRPF found 23 spent bullets and a pair of discarded hawaii chappals close to the grave on Tuesday.Meanwhile, the son of a BUPC supporter, Haren Pramanik, whose house is located near the grave and who has been missing since November seven when CPM supporters attacked a BUPC procession, was present during the exhumation.Another villager, also a BUPC supporter, Mahitosh Karan who lives nearby and whose son was missing was also at the graveside.Earlier on December 5, five graves were found at Bidyapith village at the CPM stronghold of Khejuri and the Talpati canal at Bhangabera, a BUPC stronghold.Charred skulls and bones were found from the graves at Bidyapith village by the CRPF while bones were found from the Talapti canal by the CBI.