The incident occurred in February 2008 after the two officers had detained the man, who was high on amphetamines, according to documents from the prosecutor’s office.

Before they handed the man over to staff at the psychiatric clinic, the officers instructed him to wish their colleague happy birthday while they recorded the greeting with a mobile phone camera.

The film was then sent to the fellow officer’s mobile phone using a picture messaging service.

Employees at the hospital were so upset by the incident that they reported the matter to police and a preliminary investigation was launched by head prosecutor Kristian Augustsson.

Under questioning by the prosecutor, one of the officers admitted to the events, but claimed that the detained man had agreed to the prank.

Augustsson subsequently abandoned the case after he couldn’t prove a crime had taken place.

Nor were there grounds for formally disciplining the officers, according to documents from the country police commissioner’s office.

However, the chief of police in Malmö has been asked to have a conversation with the two officers in question.