On the night of April 1, 1865 at 11:00 p.m., Parke sent men from Brigadier General Simon G. Griffin's brigade of Brigadier General (Brevet Major General) Robert B. Potter's division forward from a point near Fort Sedgwick (also known as "Fort Hell") to take Grimes's picket line. They captured 249 officers and men, about half of Colonel Edwin L. Hobson's brigade in the process. Parke was still quite concerned about trying to assault these works and pointedly asked that the offensive be cancelled since the element of surprise had been lost. Early artillery fire starting at 10:00 p.m. on April 1 and the attack on the picket line and subsequent skirmishing had put the defenders on alert.