Self-proclaimed Islamist terrorist Mohammed Merah was killed in a hail of gunfire early Thursday morning as French police stormed his apartment in Toulouse. The violent end to a story that shook France and the world followed a daylong standoff during which Merah communicated with French police forces, threatening them with lethal violence if they attempted to arrest him for murdering seven people, including three children.

As the dust settled the details of Merah's life began to emerge, painting a picture of a troubled young man who was swept up in and radicalized by Middle Eastern jihadism. Here are five important things to know about Mohamed Merah and the violence he caused.

Troubled youth: Mohammed Merah was born in Toulouse, a metropolitan city in southwest France, in 1998 to an Algerian mother and a French father, and grew up in the crime- and drug-ridden suburb of Les Izards. He had two sisters and two brothers. Following the murders committed by Merah, one of his brothers was arrested by French authorities while the other turned himself in to be questioned.

In his youth, Merah often came across as a quiet young man, according to his neighbors. He worked at a garage in a nearby suburb, but according to Paris prosecutor Francois Molins, Merah spent his time at home watching violent Muslim jihadist videos, including footage of beheadings. He was also sentenced on 15 separate occasions in the Toulouse juvenile court.

Merah tried to join different branches of the French army on two separate occasions. The first time was at the opopsite end of France in the northern city of Lille, where he was turned away for his prior convictions. In July 2010 he began enlistment in the Foreign Legion, but mysteriously walked away following the first round of testing.

Exposure to radical Islamism: Merah spent a considerable amount of time in Afghanistan and Pakistan, but little is known about what triggered his radicalization. He first read the Quran while serving time in French prison, and was likely exposed to radical ideologies while living in the Middle East. Christian Etelin, a lawyer who had represented Merah for previous minor offenses, confirmed that his client was in Afghanistan two years ago. Etelin told the CNN that Merah became suddenly radicalized and decided to become more politically involved.

Molins told the press that Merah claimed to have trained with al Qaeda in Pakistan's Waziristan region, bordering Afghanistan. Merah was picked up at a traffic stop in Afghanistan in 2010. Afghan police reported him to international forces, who deported him back to France.

Etelin described Merah as having a complex personality. They last saw each other on Feb. 24, when Merah appeared in court to face charges of driving without a license and causing an accident resulting in injuries. Merah would have appeared before the court again this April for the same case.

I never discussed his political ideas with him. I knew he was politically active but he never spoke to me about this. He didn't want to talk about this, Etelin said. He was very discreet on this. But I never had the impression that he was an individual radically different from the one I knew in the beginning. I always knew him as being someone very flexible in his behavior, courteous, polite, soft and certainly not rigid to the point of being led by a certain fanaticism.

Staying off the French government's radar: Despite Merah's interest in the Middle East and his troubled childhood, the French counterterrorism unit never took an interest in him until it was far too late. Molins, who is France's counterterrorism chief, disputed claims that French intelligence failed to stop Merah earlier by picking up on obvious signs. Merah did not follow the traditional route to radical Islam. He did not join any Islamist networks, which the French government would have picked up on, Molins said.

However, that didn't stop the FBI from putting Mohamed Merah on a terror watch list in 2010, after he was first detained in Afghanistan. Merah was barred from all flights to the U.S. for the past two years. There are more than a million people on the FBI's terror watch list, according to the ACLU.

A methodical killer: Between March 11 and 21, Merah killed seven people. Each crime was carefully planned out -- Merah told police that he videotaped his victims beforehand although no online footage has been discovered so far -- and killed most of his victims point blank with gunshots to the head. His victims were all carefully selected. The first three murders targeted French soldiers of North African origin. On March 19 he attacked a Jewish school in Toulouse, killing three students and a rabbi.

Self-styled Islamic martyr: Mohamed Merah's actions appear to have been specifically chosen to emulate jihadist martyrs of the past. After fleeing the school on Monday he holed up in his Toulouse apartment, which he had stocked with guns, ammunition and the necessary ingredients to build a petrol bomb. According to Molins, he was also wearing a bulletproof vest.

CNN terrorism analyst Paul Cruickshank noted that Merah died in what al Qaeda would consider a blaze of glory, since he was defiant until the end and was still firing at the police until the moment they killed him.

Merah told the police that he was acting alone, and had intended to continue carrying act terrorist attacks. He told police his only regret was not successfully killing more people and boasted that he had brought France to its knees. However, he also stated that this was never a suicide mission.

President Nicolas Sarkozy maintained that every effort was made to take Merah into custody alive, but near the end the police decided it was not worth putting even more lives at risk.

Interior Minister Claude Gueant said a Special Forces expert told him they had never encountered a suspect who resisted so ferociously.

He claims to be a jihadist and says he belongs to al Qaeda, Gueant said. He wanted to avenge the Palestinian children and take revenge on the French army because of its foreign interventions.