Lawcius it is.
Laevinus Coffeium probably could have strengthened his position by waiting for further reinforcements, as his army was quite limited. However, so were the defences in this area, and he would not suffer honor(his, Rome's, both) to be sullied for a moment longer.
There were a couple units of light infantry outside Herakleia sent to bolster defenses, and Coffeium took after them first. He attacked at night to prevent the garrison from coming out and assisting them, and it wasn't much of a fight. Here, Roman spearmen can be seem pursuing the shattered remains of the Aiakid ranks.
Laevinus destroyed the relief force, none of the estimated 3300 he faced lived to tell the tale, while his casualties were only a little over 500. Having dispensed with that complication, the siege began -- winter or no.