On August 23, 1973, Jan Erik Olsson, on leave from prison, walked into Kreditbanken (now part of Nordea) at Norrmalmstorg, central Stockholm and attempted to hold up the bank. Swedish police were called in immediately, two of them went inside, and Olsson opened fire, injuring one policeman. The other was ordered to sit in a chair and "sing something". He started singing "Lonesome Cowboy". Olsson then took 4 people as hostages. He demanded his friend Clark Olofsson to be brought there, along with 3 million Swedish Kronor ($730,000 US 1973 value), two guns, bullet-proof vests, helmets and a fast car. Olofsson was a repeat offender who had committed several armed robberies and acts of violence, the first committed at the age of 16.
Olofsson was brought in by permission of the government and established a communication link with the police negotiators. One of the hostages, Kristin Enmark, said she felt safe with Olsson and Olofsson but feared 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 up the Prime Minister Olof Palme and said he would kill the hostages, backing up his threat by grabbing one in a stranglehold; she was heard screaming as he hung up.
The next day Olof Palme received another call. This time it was Kristin Enmark who said she was very displeased with his attitude, asking him to let the robbers and the hostages leave.
Olofsson walked around in the vault singing Roberta Flack's "Killing Me Softly".
The drama went on. On August 26, the police drilled a hole into the main vault from the apartment above. From this hole a widely circulated picture of the hostages with Olofsson was taken.
Olsson fired his weapon and threatened to kill the hostages if any gas attack was attempted. On August 28 the gas was used anyway, and after half an hour Olsson and Olofsson surrendered. No one was physically injured.
Olsson was sentenced to 10 years in prison. He received many admiring letters from women who found him attractive. He later became engaged to one of them (not one of the hostages, however, as some state). After his release, he appears to have carried on with unlawful activities. 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 still repeatedly claim they were more frightened of the police than the robbers during their six days of confinement. They clearly sympathized with their captors, which has led to academic interest in the matter. The term "Stockholm syndrome" was coined by criminologist Nils Bejerot.
The most widely publicized myth about the robbery, or rather about the Stockholm syndrome, was that one or both robbers became engaged to their captives. This is simply not true, and may stem from the language barrier: the phrase "engagera sig i någon" in Swedish does not mean "to become engaged to someone" (which would be "att bli förlovad med någon"), but rather "to care deeply about someone" (this sort of resemblance between two words in different languages that are not synonyms is known as a false friend).
As stated above, Kristin Enmark and Clark Olofsson became friends, and Jan Olsson married one of his female admirers, but there were no engagements between anyone present during the events.
British rock band Muse and American rock band Blink-182 both have songs entitled "Stockholm Syndrome", the former on the album Absolution and the latter on its self-titled album. The American band Yo La Tengo also has a song of the same name on its album "I Can Hear the Heart Beating as One."