20. The Union troops inside Fort Wagner shifted to the defensive
With no fresh troops moving forward to support them the Union troops within Fort Wagner shifted to defending themselves from Confederate counterattacks. Putnam tried to organize a fighting withdrawal before he was hit in the head, dying instantly. Major Lewis Butler of Ohio began withdrawing troops under fire, in small groups at first, while others used makeshift cover within the fort to resist Confederate assaults. Meanwhile, fresh troops from Charleston were ferried to Morris Island and joined in the assault on the remaining Union troops. The Union men either died, surrendered, or ran for their lives. Many who attempted to surrender were shown no quarter.
Gradually the firing died down, though many of the wounded remained where they lay throughout the night. Confederate troops who spotted wounded black troops shot or bayoneted them. The daylong bombardment and the wave of assaults had cost the Confederate garrison 36 killed, and about 140 wounded. The Union troops suffered over 1,500 casualties. The 54th Massachusetts suffered 281 casualties, nearly half of the men who had advanced into battle behind Colonel Shaw. 54 were known dead, and another 48 were never heard from again, presumably, they were also killed by the Confederates during the fighting or once it was over.