LIEGE, Belgium — Belgians sought to make sense Wednesday of a spasm of killing by a man with a history of trouble with weapons and drugs who unleashed his attack near a Christmas market at a historic square, bringing random death to a familiar scene of European holiday bustle.

The attacker, identified as Nordine Amrani, 33, killed a toddler and two teenage boys and left more than 120 wounded, with five still in intensive care on Wednesday. Amrani killed himself with a bullet to the forehead.

Compounding the gruesomeness of the case, the police found the body of a woman at a building he used to store guns, and, in the past, to grow marijuana. Prosecutors said they believed Amrani killed her before he went to the square.

Friends of the dead and injured laid flowers and lit candles Wednesday at the Place St.-Lambert.

A Belgian of Moroccan descent whose troubled history showed no sign of Islamic extremism, Amrani had been summoned to appear before the police about a case of sexual abuse at around the time of the attack. Instead, he armed himself and mounted some kind of desperate, final lashing out.