LIEGE, Belgium - Investigators have found the body of a woman in a shed belonging to the gunman who killed four people and wounded 125 in eastern Belgium on Tuesday.

The body was found following an overnight search of the building, which police said shooter Nordine Amrani had used to grow cannabis.

---

The 33-year-old brought carnage to the eastern city of Liege by hurling grenades and spraying bullets into crowds of Christmas shoppers.

Two boys aged 15 and 17 were killed, along with a 75-year-old woman and a toddler of just 17 months, whom hospital doctors fought for hours to save.

• PhotoBlog: Attacker throws grenades into Belgium city center crowd

It was still unclear what drove Amrani to carry out the attack, and investigators were trying to build a profile of the man.

He was previously jailed for possession of arms and drugs offenses.

On the morning of the killings he had been called in for questioning by police in a sexual abuse case, the Associated Press reported.

Police said the body of his fifth victim was a 45-year-old woman who worked as a cleaner for one of his neighbors.

Prosecutor Cedric Visart de Bocarme told Belgian La Premiere radio station: "A search last night revealed in a warehouse used by the attacker, notably to grow cannabis, the body of a woman killed by the attacker before he went to the Place Saint Lambert.

"The enormous concern we have is how it was possible for someone seemingly sensible and normal to do this. It was a delinquent, someone who had difficulties throughout their life."

Previous conviction
Amrani was freed from jail about a year ago following a 2008 conviction for illegal possession of arms and for growing a huge field of cannabis. A report in Britain's Daily Telegraph said police found 10 firearms and 9,500 gun parts along with 2,800 cannabis plants, but a prison official granted Amrani early release last year.

The report said he was a weapons aficionado and was said to be able to dismantle, repair and put together a number of different weapons but was never linked to any terrorist act or network.

"He has no history of terrorist acts," prosecutor Daniele Reynders told a news conference on Tuesday.

Instead of reporting to the police station as requested on Tuesday, he took a light automatic rifle, a handgun and several grenades and went onto the roof of a bakery in the central Saint-Lambert square before hurling the weapons into the crowd.

How exactly he died was not immediately clear, with some witnesses claiming he turned his revolver on himself while others said one of his grenades appeared to explode prematurely.

Liege's mayor, Willy Demeyer, said the two teenage victims had been taking school exams nearby just before the attack.

At Amrani's most recent address, an apartment block near the scene of the attack, Johan Buron said he had been astonished to learn what his neighbor had done.

"He was calm, every time I met him in the corridor he was very friendly and said 'Hi'," he told Reuters. "If my memory serves me right, he was a welder."

Random killings are rare in Belgium. Most recently, in January 2009, a man stabbed two infants and a woman to death and injured 13 at a nursery in the town of Dendermonde.

Reuters, The Associated Press and msnbc.com staff contributed to this report.

Read more content from msnbc.com and NBC News:

• Hunt for terrorists shifts to 'dangerous' North Africa, Panetta says
• US halts $700 million in Pakistan aid, demands action on Taliban
• Chinese artist depicts portraits of corruption
• 4 killed in grenade attack on Belgium market
• New laws protect women from abuse in Pakistan
• Netherlands proposes ritual slaughtering ban