Nationalist politicians everywhere think they know exactly what happened on Monday night in Berlin, where a heavy truck ploughed into a Christmas market, killing 12 and injuring 50.
The police and prosecutor's office, by contrast, don't pretend to know - a fact that makes me proud to be living in Germany.
Many have immediately jumped to the conclusions that best serve their interests.
Dutch Freedom Party leader Geert Wilders, a surprisingly strong contender in his country's upcoming election, tweeted a picture of German Chancellor Angela Merkel spattered in blood and accused her - along with Dutch Prime Minister Mark Rutte and other centrist leaders - of "letting in Islamic terror" with their open-border policies.
French nationalist leader Marine Le Pen asked "how many massacres and deaths" it will take to get governments to close borders.
Austrian nationalist leader Heinz-Christian Strache called for "a common approach against the radical threads of Islam".
"The civilised world must change thinking!" tweeted US President-elect Donald Trump.
His British friend Nigel Farage predicted that "events like these will be the Merkel legacy".
In Germany, leaders of Alternative for Germany (AfD), an anti-immigrant, anti-European Union party, rushed into the opening. "When does this cursed hypocrisy finally stop?" tweeted Mr Marcus Pretzell, an AfD regional leader. "These are Merkel's dead!" The party's national co-leader, Ms Frauke Petry, also ranted about Dr Merkel's open-door policy for refugees as the cause of the Berlin deaths.
Meanwhile, German police, prosecutors and their political bosses have stuck impressively to the facts. At a press conference early yesterday, Interior Minister Thomas de Maiziere called the incident an "attack", but pointedly stopped short of saying "terror attack".
Later, Prosecutor-General Peter Frank added the world "terror" but wouldn't venture as far as "Islamist", though he did note that the script of the attack followed some jihadist calls to arms and recalled the gruesome events in Nice last July. It's a professionalism and precision that I much prefer to the nationalists' sweeping assumptions.
Minutes after the attack, police detained a man they suspected of being the truck's driver. A witness apparently followed him for more than a mile, talking all the while to the police, who finally picked him up in the middle of Tiergarten - a big central park where it would have been easy to hide in the dark.
The man, a 23-year-old Pakistani, applied for refugee status in Germany early this year and was living in one of the disused hangars at the former Tempelhof Airport that the city started using last year as temporary shelters.
The hangars are hardly an environment conducive to sanity. Hundreds of people are still living there, sleeping in makeshift, windowless enclosures that - though clean and well-supplied - have walls that don't reach the high ceiling and echo with the slightest sound. It was easy to imagine a likely story for the suspect: A perilous journey to Germany over the Balkan route, a long wait while the overburdened bureaucracy processed his application, joyless existence at the abandoned airport with no prospect of finding work, petty crime, Islamist propaganda on the Internet, then finally an attack.
On Tuesday, however, police and prosecutors reported that the man was denying his involvement. That wouldn't be typical behaviour for an Islamic State in Iraq and Syria (ISIS) fanatic. In their precise yet open manner, the German law enforcers were both warning citizens that the perpetrator - or perpetrators, as the case might be - could still be at large, and withholding judgment as to the motives of the attack.
ISIS has since claimed responsibility for the crime.
Recently, a video of a man brutally kicking a woman down the stairs in the Berlin subway went viral in Germany. Predictably, many blamed the refugees. After weeks of searching for the suspect, police arrested an EU citizen from Bulgaria, bitterly disappointing the nationalists, who switched to screaming that the man had lived in a predominantly Roma-populated slum in Varna - which, in their eyes, made him a second-class citizen anyway.
While the unseemly debate went on, German police methodically did their job. If the Berlin attacker or attackers have not been caught yet, investigators will again ignore all the political wing-flapping and keep digging for the truth.
Police have their work cut out for them. Germany has 2,500 Christmas markets - it's a particularly revered tradition, and few neighbourhoods are without a gaggle of stands selling sausage, mulled wine and handicrafts. The markets, as Monday's events proved, are an easy target, and stubborn Germans won't stop visiting them just because of the truck. That means more vigilance, already visible in the form of an increased police presence.
The incident and its aftermath won't, however, destroy the spirit of this vital, unsentimental, vastly tolerant and wildly mischievous city. Berlin will mourn, as it often has, and it will move on as it has always done.
So will Dr Merkel. After hundreds of attacks on women in Cologne last New Year's Eve, no similar outbreaks have taken place. The government has moved to deport more people, accept fewer new immigrants and speed up application processing. An integration law was passed, making it clear that newcomers are expected to assimilate.
As much as nationalist hotheads may hope that the attack will mark the end of Dr Merkel's career, the 2017 election is still far off. Voters are watching both the "I told you so" hysterics from the right and the government's professional actions and communication.
Dr Merkel will be running on her skill as a crisis manager, not merely on an open-door policy. The latest attack is a test - far from the first one she has faced, but hopefully the last of its kind.