When German authorities announced that Anis Amri, a Tunisian national suspected of driving a truck into a Christmas market in Berlin, had been on their radar for more than a year, questions arose as to how and why he hadn't been apprehended beforehand.

Despite allegations of petty crime, a failed asylum application and telling an intelligence informant that he wanted to commit an attack on German soil, the 24-year-old managed to slip through the sprawling web of national security and law enforcement agencies.

Clemens Binninger, deputy chairman of the parliamentary oversight panel for intelligence services, told public broadcaster Deutschlandfunk on Tuesday that there needed to be a "much clearer leadership at the federal level" to cope with terrorist threats after Amri's attack left 12 dead and dozens more injured.

"In the case of Amri, about 45 authorities or agencies have been involved at some point in the past year and a half, including police stations, news services, state police agencies, the Federal Criminal Police Agency, foreign authorities, North Rhine-Westphalia's interior ministry and public prosecutors. About 45. How is it possible to achieve a uniform procedure?" he said.

Although Amri's case passed through dozens of offices involved in counterterrorism activities, his most notable slip through the cracks of intelligence and immigration authorities raised concerns that law enforcement agents needed more tools to quickly deal with possible threats.

'Radical mindset'

In November 2015, Amri unintentionally told an informant for the Federal Criminal Police Agency (BKA) in the German state of North Rhine-Westphalia that he wanted to "do something in Germany" and could acquire an AK-47 assault rifle in order to commit an attack, according to the Munich-based daily "Süddeutsche Zeitung."

"Amri's behavioral patterns indicate a possible intensification of attack planning and confirm the depth of his radical Islamic mindset," the "Süddeutsche Zeitung" reported, quoting an intelligence service document.

Although he was eventually placed under surveillance in March due to his likely tendency for extremist action, authorities ended monitoring activities in September after he failed to raise suspicions.

German intelligence services classified him as an "unlikely" threat, describing him as a mere "errand boy" connected to radical Iraqi preacher Abu Walaa, reported Hamburg-based news magazine "Der Spiegel."

While much of the information gathered by state-level authorities had been provided to Germany's Joint Counter-Terrorism Center (GTAZ), a "joint co-operation and communication platform used by 40 internal security agencies," action could not be taken due to a lack of incriminating evidence, Justice Minister Heiko Maas said earlier this month.

The North Rhine-Westphalia question

In the meantime, immigration authorities in North Rhine-Westphalia rejected Amri's asylum application in June, effectively flagging him for deportation. However, Tunisia failed to recognize Amri as a citizen, effectively blocking Germany from returning him.

While German authorities waited for an official passport to deport Amri, Tunisia eventually confirmed his identity and in October transmitted the failed asylum seeker's personal data.

Binninger, who also serves as a security expert for Chancellor Angela Merkel's ruling conservative Christian Democratic Union (CDU), questioned why law enforcement officers in the German state did not apprehend the failed asylum seeker after receiving his personal data.

Although German law only allows for the detention of asylum seekers if their deportation is likely within three months, Amri could have been held after Tunisia confirmed his identity and transmitted his data, according to Binninger.

"The question is: why did authorities in North Rhine-Westphalia not do anything to catch him and take him in for deportation from October onwards?" he asked.

Remedies and disappearances

German officials have vowed to remedy the question of deportation for failed asylum seekers considered a possible threat.

Interior Minister Thomas de Maiziere and Maas earlier this month proposed pre-deportation detention of up to 18 months or ankle bracelets for monitoring. Other measures included making deportation easier, increased surveillance on potentially-dangerous individuals and stringent residence obligations for identity fraud.

More than 500 individuals have been classified in Germany as a potential threat, roughly half of them non-German nationals, according to de Maiziere.

Lawmaker Burkhard Luschka of the center-left Social Democrats (SPD), junior coalition partners to the CDU, told a German parliamentary committee on Tuesday that three of them have disappeared from authorities' radar, according to Germany's DPA news agency.