A British soldier patrols with an armed police officer near parliament in central London on May 24, 2017 | Justin Tallis/AFP via Getty Images Manchester bomber flew from Turkey four days before attack: report Salman Abedi flew from Istanbul to the U.K. via Düsseldorf, Germany.

Salman Abedi, identified as Manchester Arena bomber, flew from Turkey to the U.K. four days before carrying out the attack that killed 22 people Monday, the Financial Times reported Thursday, citing German intelligence sources.

Abedi flew from Istambul to the U.K. via Düsseldorf, Germany, according to the sources. Information on Abedi was passed on to British authorities Wednesday, according to a Turkish official cited by the FT.

German magazine Focus reported Thursday that 22-year-old Abedi had been spotted in Germany at least twice, once in Düsseldorf four days before the attack and on a flight from Frankfurt to the U.K. in 2015.

U.K. authorities and counter-terrorism experts are investigating whether Abedi was in touch with Isis or other radical Islamic groups, which would make him part of a broader terrorist network.

Abedi is thought to have traveled to Syria, French officials reported. While Turkey is known as a transit point to Islamic State territory, whether Abedi spent time there just before the bombing remains unclear.