A lorry ploughed into a busy Berlin Christmas market yesterday, killing 12 people in what German Chancellor Angela Merkel called a "terrorist attack".
A Pakistani asylum seeker was arrested a short time afterwards but police released him for lack of evidence, and the so-called Islamic State group claimed the attack.
Here is what we know of the event, which was reminiscent of the horrific scenes in July when a truck drove into a crowd in the French Riviera city of Nice.
What happened?
Around 8pm local time a lorry drove for up to 80 metres into a busy Christmas market frequented by locals and tourists, smashing wooden stalls and crushing victims.
Twelve people were killed and at least 48 injured.
A Pakistani asylum seeker held on suspicion of driving the Polish-registered truck was detained a short time later but this evening police released him after forensic tests failed to show he had been in the lorry's cab.
Police said a passenger was found shot dead in the cab of the lorry and later identified him as a Polish national.
The deadly event took place in the shadow of the Kaiser Wilhelm Memorial Church whose damage in a World War II bombing raid has been preserved as a reminder of the horrors of war.
An attack?
Chancellor Merkel said the attack was a "terrorist act" and voiced fears speaking before police backtracked on the Pakistani detainee that the rampage was committed by an asylum seeker.
The interior ministry said there was no reason to close Germany's popular Christmas markets. "We must not let our free way of life be taken from us," it said in a statement.
The federal prosecutor's office has taken over the investigation, a routine step when terrorism is suspected.
A jihadist linked news agency said tonight that someone from the so-called Islamic State had carried out the attack "in response to appeals to target citizens of coalition countries."
The suspect
Earlier today, Berlin's police chief warned that the "dangerous criminal" behind the attack may still be at large.
"It is the case that we may have a dangerous criminal in the area and that of course makes the public nervous," said Klaus Kandt, adding: "Of course we are boosting security measures.
"Heightened vigilance is also needed right now."
The lorry
The Polish owner of the lorry confirmed late last night that his driver was missing, while German officials said today that a Polish man found dead after the carnage was "shot" dead.
"One of the victims was shot," said Karl Heinz Schroeter, interior minister of neighbouring Brandenburg state, without specifying whether this victim was the registered driver of the truck.
The company's transport manager, Lukasz Wasik, said the driver was 37-years-old and had been transporting Thyssen steel products from Italy to Berlin.
