Missed chances: How Berlin attack suspect slipped through net

As police hunt for Tunisian Anis Amri, the top suspect in Berlin's Christmas market attack, public anger has grown over a catalogue of failures that allowed him to evade arrest or deportation.
An incredulous public has learned that Amri was a rejected asylum seeker and known radical jihadist with a history of crime who had been under police observation for plotting an attack before surveillance was dropped.
"They knew him. They did nothing," ran the scathing headline of Berlin's B.Z. Tabloid.
Here are the missed chances that may have prevented Monday's attack, according to what we know so far from official statements and press reports.

It seemed too good to be true when police said Monday night they had arrested a suspect within an hour of the attack -- a Pakistani man who had apparently been identified by an eyewitness.
By the time police let him go late Tuesday for lack of evidence, they had lost 24 hours during which the public had not been told the armed killer was still on the run.

Police say a forensics team only found a wallet containing Amri's papers in the truck cabin on Tuesday afternoon.
It took until yesterday afternoon for authorities to issue a Europe-wide public wanted notice that gave Amri's full name, age and photograph and warned the public he was dangerous.

Amri had been watched since March by counter-terrorism services who knew he was in contact with radical Islamists and could have been plotting an attack.
He had had contact with Iraqi "hate preacher" Ahmad Abdulaziz Abdullah A, who was arrested by German police in November for setting up a recruitment network on behalf of the Islamic State group.
Berlin prosecutors say Amri had been suspected of planning a burglary meant to raise cash to buy automatic weapons, "possibly to carry out an attack".
Surveillance had however shown that Amri was working as a small-time drug dealer in Berlin, and the observation ended in September.

Amri had used different identities to travel between German states, an unnamed investigator told the Bild newspaper, "but apparently there was never sufficient evidence to arrest him".
Der Spiegel news weekly said security services had even heard Amri volunteer for a suicide attack -- but that he had used a phrase considered too obscure to stand up as evidence leading to an arrest.
Amid the finger-pointing, debate is raging over whether Amri's case highlights incompetence or an overburdened security apparatus.