The Norrmalmstorg robbery was a bank robbery and hostage crisis best known as the origin of the term Stockholm syndrome. It occurred at the Norrmalmstorg Square in Stockholm, Sweden, in August 1973 and was the first criminal event in Sweden to be covered by live television. Jan-Erik Olsson was a convicted criminal who had disappeared while on furlough from prison and then held up a bank and took four hostages. During the ensuing negotiations, Swedish Minister of Justice Lennart Geijer allowed Olsson's former cellmate and friend Clark Olofsson to be brought from prison to the bank. Although Olofsson was a long-time career criminal, it is doubtful he was in league with Olsson. Famously, the hostages then bonded with their captors and acted to protect them despite their repeated threats to kill them all. Police finally mounted a tear gas attack five days into the crisis, and the robbers surrendered. Olsson was sentenced to 10 years for the robbery, and Olofsson was ultimately acquitted. The paradoxical actions of the hostages led to a great deal of academic and public interest in the case, including a 2003 Swedish television film, a 2018 Canadian film and a Swedish Netflix television series premiering in 2021. 
Jan-Erik Olsson was on leave from prison on 23 August 1973 when he went into Kreditbanken at Norrmalmstorg, Stockholm and attempted to rob it. Swedish police were notified shortly after and entered the bank. One officer, Ingemar Warpefeldt, suffered injuries to his hand after Olsson opened fire, while another was ordered to sit in a chair and sing a song. Olsson then took four people hostage and demanded his friend Clark Olofsson be brought there, along with three million Swedish kronor, two guns, bulletproof vests, helmets and a car.
Olsson was a repeat offender who had committed several armed robberies and acts of violence, the first when he had been 16.
The government gave permission for Olofsson to be brought as a communication link with the police negotiators. The hostage Kristin Enmark said that she felt safe with Olsson and Olofsson but feared that the police might escalate the situation by using violent methods. Olsson and Olofsson barricaded the inner main vault in which they kept the hostages. Negotiators agreed that they could have a car to escape but would not allow them to take hostages with them if they tried to leave.
Olsson called Swedish Prime Minister Olof Palme, said that he would kill the hostages and backed up his threat by grabbing one of them in a stranglehold. She was heard screaming as he hung up. The next day, the hostage Kristin Enmark called Palme, said that she was very displeased with his attitude and asked him to let the robbers and the hostages leave.
Olofsson walked around the vault and sang Roberta Flack's "Killing Me Softly". On August 26, the police drilled a hole into the main vault from the apartment above and took a widely-circulated photograph of the hostages with Olofsson. Also, Olofsson fired his weapon into the hole on two occasions and wounded a police officer in the hand and the face.
Olsson had fired his weapon and threatened to kill the hostages if any gas attack was attempted. Nevertheless, on August 28 police used tear gas, and Olsson and Olofsson surrendered after an hour. None of the hostages sustained permanent injuries.
Both Olsson and Olofsson were charged, convicted, and sentenced to extended prison terms for the robbery. However, Olofsson claimed that he had not helped Olsson but had only tried to save the hostages by keeping the situation calm. The court of appeal quashed Olofsson's convictions. He later met the hostage Kristin Enmark several times, and their families became friends. He later committed further crimes.
Olsson was sentenced to 10 years in prison. He received many admiring letters from women who found him attractive. (He later got engaged to a woman who was not, despite what some state, one of the former hostages.) After his release, he is alleged to have committed further crimes. After having been on the run from Swedish authorities for ten years for alleged financial crimes, he turned himself in to police in 2006, only to be told that the charges were no longer being actively pursued.
The hostages sympathised with their captors, which has led to academic interest in the matter. The Swedish term Norrmalmstorgssyndromet (Norrmalmstorg syndrome), later known as Stockholm syndrome) was coined by the criminologist Nils Bejerot. The hostages, although they were threatened by Olsson, never became violent toward the police or toward each other.
In 1996, Jan-Erik Olsson moved to northeastern Thailand with his Thai wife and son, and moved back to Sweden in 2013. Olsson's autobiography Stockholms-syndromet was published in Sweden in 2009.
In popular culture
The 2003 television film Norrmalmstorg, directed by Håkan Lindhé, is loosely based on the events. A fictionalized version of the robbery is told in Stockholm, a 2018 Canadian film directed by Robert Budreau.
Netflix is producing a 6 episodes series named Clark directed by Jonas Akerlund and starring Bill Skarsgård as Clark Olofsson, set to premiere in 2021.
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