A man drove a van into a crowd at Berlin’s Christopher Street Day celebrations late on Saturday and then attacked bystanders with a bladed weapon, killing a woman and injuring 29 people, several of them critically. Police shot the suspect dead on Sunday afternoon after a manhunt lasting nearly 24 hours, ending one of the most serious attacks on a public gathering in the German capital in years.

The vehicle struck pedestrians in the Tiergarten near the Brandenburg Gate at about 10pm, after hours of peaceful marching by a crowd that organisers numbered in the hundreds of thousands and that moved behind roughly 80 floats. The driver abandoned the van and fled on foot, attacking others with what investigators believe was a machete before disappearing into the park. The remainder of the festival was cancelled.

Interior Minister Alexander Dobrindt identified the suspect as Abdul Ballout, a 21-year-old German citizen of Lebanese descent, and said that "everything we see here points to us dealing with an Islamic terror attack." A police spokesman, Florian Nath, said Ballout was "known to us as a member of Islamic circles here in Berlin" and that the search was proceeding at full speed.

It ended on Sunday in Spandau, on Berlin’s western edge, where officers located him at an allotment garden complex. According to the police account, he ran toward them armed with a bladed weapon and officers opened fire. Berlin’s fire service attempted resuscitation at the scene, where he died.

The detail that will shape the inquiry is his record. Ballout had already been convicted of preparing a serious act of subversive violence in connection with a failed attempt to join ISIS. That offence is Section 89a of the German criminal code, one of three provisions introduced in 2009 by a law on the prosecution of the preparation of serious violent offences endangering the state. The statute was written after the Madrid and London bombings and the discovery of suitcase bombs on regional trains at Koblenz and Dortmund, and its specific purpose was to close a gap that let people who had prepared an attack but not yet carried one out escape prosecution.

In other words, the mechanism designed to catch someone at exactly Ballout’s stage did catch him, and the attack happened anyway. German authorities have not said when his sentence ended or what supervision, if any, applied afterwards, and those are now the central questions for the federal prosecutor’s office.

Christopher Street Day is among the largest LGBTQ events in Europe and has run in Berlin since 1979, drawing crowds that in recent years have exceeded half a million. Investigators have not published a formal statement of motive beyond Dobrindt’s characterisation, and no charges will follow, since the only suspect is dead.