Berlin attacker's cell phone provides crucial details of attack, report finds

Berlin attack exposes security holes in Europe

Alex Melegrew-Hitchens, research director at George Washington University's program on extremism, weighs in

The Berlin Christmas market terrorist circled his target three times and sent pictures and voice messages on a cellphone up to ten minutes before the Dec. 19 attack, Germany's Focus magazine reported Wednesday.

Investigators reportedly uncovered the details after searching Anis Amri's phone.

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Authorities have sought eyewitness accounts and phone images from passersby due to an odd lack of surveillance cameras in the busy locale.

After driving his truck into a crowd at the market, killing 12 and injuring 48, Amri began a 1,200-mile trek to Italy that officials are still investigating. Amri journeyed through five European countries over several days -- all while he was the most-wanted man in Europe.

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Amri, 24, was killed in a shootout with police in a suburb of Milan early Friday.

German prosecutors said Wednesday that they detained a Tunisian man they think may have been involved in the truck attack. Officials linked the man to Amri also by searching Amri's cellphone.

The 40-year-old, who wasn't identified, was detained during a search of his home and business, federal prosecutors said.

Prosecutors said in a statement that "further investigations indicate that he may have been involved in the attack."

Authorities have until Thursday evening to determine whether the case against the 40-year-old is strong enough for them to seek a formal arrest warrant. That would allow them to keep him in custody pending possible charges.

Investigators are trying to determine whether Amri had a support network in planning and carrying out the attack, and in fleeing Berlin.

Fox News' Greg Palkot and The Associated Press contributed to this report.