The six-day siege at Kreditbanken on Norrmalmstorg square saw hostages develop sympathetic bonds with their captors, resisting rescue and later defending the robbers publicly. Psychiatrist Nils Bejerot, who advised the police, called it 'Norrmalmstorgssyndromet', later known internationally as Stockholm syndrome, and the term entered common usage after the crisis ended on August 28.
On August 23, 1973, escaped convict Jan-Erik Olsson took four employees of Kreditbanken hostage in central Stockholm, later joined by an accomplice, Clark Olofsson, whom Olsson demanded be brought from prison. Over six days, police negotiated while the hostages remained locked in the bank's vault with their captors, an ordeal broadcast live across Sweden.
What startled observers was not the crime itself but the hostages' behavior. As the days passed, they grew to trust and even defend their captors, resisting police rescue attempts out of fear the police, not the robbers, would get them killed. After police finally used tear gas to end the standoff, several hostages hugged and kissed their captors before being led away, and some later raised money for their defense or visited them in prison.
Criminologist and psychiatrist Nils Bejerot, who had advised police during the standoff, described the phenomenon for Swedish media as hostages bonding with aggressors under extreme stress as a survival mechanism. The term spread internationally soon after and gained wider fame when it was applied to Patty Hearst's 1974 kidnapping. Decades later, psychologists still debate whether Stockholm syndrome is a distinct clinical condition or simply a vivid label for a form of trauma bonding, but the phrase has become permanently embedded in popular language.