The university had initially opted to educate students virtually, due to the COVID-19 pandemic in Germany, but it resumed in-person learning in October 2021.

[3][4] The campus at Neuenheimer Feld, north of the Neckar, is mainly home to the natural science faculties and properties of the university hospital.

[5] The 18-year-old gunman reportedly sent a text message on WhatsApp to his father[6] directly before the shooting, claiming "people have to be punished now" and demanding a burial at sea.

He entered a lecture hall located in INF 360 building at the campus, carrying a double-barreled shotgun (Akkar Churchill 512, 12 gauge) and a lever action rifle[3] (Chiappa Firearms Model 1892[7]), and opened fire with the shotgun on the crowd of 30 freshman students, who were participating in an ongoing organic chemistry class.

[11] The shooter fled the scene and was later found dead in the area of the Botanical Garden nearby; his death was ruled by investigators to be a suicide.

[3] Officers were spotted examining two firearms and a beige bag found in the nearby Heidelberg University Botanical Garden close to the scene.

[19] Shortly after the attack the chief of Heidelberg's public prosecutor's office said it was too early to speculate on a possible motive for the gunman's actions.

[9] According to Mannheim Police Department president Siegfried Kollmar, the gunman, Nikolai G.,[27][28] was an 18-year-old male student originating from the Wilmersdorf borough of Berlin.

[30] He was enrolled as a biology student and was considered healthy, but according to Süddeutsche Zeitung, there are indications of a past mental illness.

[35] According to investigative results made public in March 2022, Nikolai G. was a "loner" who did not have any social relationships with fellow students.

[36] Furthermore, a forensic psychiatrist ordered to investigate the case by the local District Attorney told reporters that the gunman's Narcissistic personality disorder was an "essential reason" for the shooting.

The investigators therefore suspect that Nikolai G. felt "extremely humiliated" and "fundamentally misunderstood" for no particular reason during his first term at Heidelberg University, which could have been a motive for the shooting.

Baden-Württemberg's Minister of Science Theresia Bauer visited the shooting site and met with the university rector Bernhard Eitel.

At 12:24, exactly one week after the shooting there was a minute's silence across the entire city, with people gathering in the University Square and in front of the central Mensa, where candles and flowers had been placed.