The Manchester bomber visited Germany just four days before launching his attack, it has been revealed.
Intelligence sources told Focus Online Salman Abedi flew from the city of Düsseldorf to Manchester, but was not on an international database or a list of potential Islamists being tracked through Europe.
German police are now investigating whether Abedi, who had reportedly visited Germany at least twice, had links to Islamist networks in the country.
In 2015 he reportedly flew from Frankfurt to the UK, while German intelligence sources said Abedi had undergone “paramilitary training in Syria”.
"The scene is closely intertwined internationally,” an official from the Federal Criminal Police Office told Focus.
"We need to clarify whether Abedi was introduced to people in Syria who he has now met in North Rhine-Westphalia or Hesse."
Both German states are home to large networks of Isis-linked extremists, with Düsseldorf known as a "hotbed" of jihadis.
Anis Amri, the Isis supporter who carried out the Berlin Christmas market attack, was linked to a cell that was shut down in November and lived with a recruiter in North Rhine-Westphalia for a time.
The state’s cities of Essen and Düsseldorf have been the target of Isis-linked terror plots foiled by police, including one by four Syrian men directly “commissioned” by commanders, sparking dozens of arrests.
German authorities have detained numerous home-grown extremists, including a national security agent in the German equivalent of MI5 accused of planning to bomb its headquarters in Cologne “in the name of Allah”.
Dozens of foreign members of Isis, al-Qaeda and the Taliban have also been detained since the arrival of more than a million asylum seekers in the refugee crisis.
Abedi’s movements inside Germany are unknown, and it is unclear whether he travelled directly to the country from the UK or from Libya, where he was previously reported to have visited.
"He went to Libya three weeks ago and came back recently, like days ago,” a friend told The Times.
Abedi and his brother had remained living in the UK after their parents, who originally came to Britain as Libyan refugees, returned to the country with their siblings.
Acquaintances said Abedi made frequent visits to Libya, coming back “a different guy” after one trip in 2011, swapping his previous lifestyle including alcohol and cannabis for apparent piety.
British security services are examining Abedi’s links to the country, where thousands of foreign fighters are believed to be embedded with warring parties including Isis.
The group has taken advantage of widespread lawlessness since the British-backed ousting of Muammar Gaddafi to gain a foothold in Libya, seizing territory and setting up terror training camps used to plan attacks in Europe.
Investigators believe Abedi was part of a larger Isis-inspired terror network, pointing to the relative sophistication of the bomb he used to massacre 22 people and injure more than 60 others at Manchester Arena.
The device, contained in a bag packed with nails, was believed to use an explosive known as TATP that has become Isis’ hallmark in atrocities including the Paris and Brussels attacks, as well as plots across Europe.
British security services are under scrutiny after leaked reports claimed Abedi’s parents had alerted authorities to his radicalisation in Manchester, persuading him to come to Libya and confiscating his passport until he claimed he wanted to go on a pilgrimage to Mecca.
The Home Secretary, Amber Rudd, admitted the 22-year-old was known to intelligence agencies “up to a point”.
Two men were arrested by police in Manchester overnight, bringing the number of suspects in custody to eight, following raids across the city and in Wigan and Nuneaton.
His father, Ramadan Abedi, was arrested in Tripoli alongside his brother Hashim, who Libyan security forces said was “aware of all the details” of the attack.
Abedi's older brother Ismail, 23, was detained in south Manchester on Tuesday.
Ramadan had earlier claimed his was innocent, saying: “We don't believe in killing innocents. This is not us.”
But a spokesperson for Libyan authorities said one of Abedi's final acts was to ring his mother, adding that Hashim had told officials: “I know everything about my brother, what he was doing there in Manchester.”
