A man friendly with members of the Hamburg al-Qa'ida cell, which launched last September's attacks on America, was formally charged yesterday.

He is only the second person to face prosecution for direct participation in the terror plot.

Federal prosecutors in Karlsruhe, Germany, did not announce specific charges against Mounir El Motassadeq, a 28-year-old Moroccan who has been in custody since 28 November last year. They said he had been charged "because of his participation in the terror attacks in the United States".

Mr El Motassadeq was enrolled as an electrical engineering student at Hamburg's Technical University, with Mohammed Atta and Marwan al-Shehhi, believed to be the two suicide pilots who brought down the World Trade Centre.

He has admitted that he exercised a power of attorney over al-Shehhi's bank account and being a signatory to Atta's will. He also acknowledged spending time at the flat shared by Atta, al-Shehhi and others, attended the same mosque and participated in the same social events.

German prosecutors claim Mr El Motassadeq was deeply involved in the financing of the 11 September plot. But they have been evasive about the charges, and they found him at home in Hamburg when other suspects had gone into hiding – which suggests that he is, at best, a peripheral figure.

Three others suspected of links to the Hamburg cell, Ramsi Binalshibh, Said Bahaji and Zakariya Essabar, vanished around the time of the attacks despite international arrest warrants out against them and have not been traced.

Mr El Motassadeq was one of 370 individuals and groups whose names appeared on a list of 11 September suspects issued by Finnish authorities last October. At the time, he denied involvement. "All of this is false, I have nothing to do with this thing," he said.

* The American government charged five men – Karim Koubriti, Ahmed Hannan, Youssef Hmimssa, Farouk Ali-Haimoud and a man known only as Abdella – in Detroit yesterday with conspiring to provide "material support and resources" to terrorists for a series of attacks in the United States, Jordan and Turkey.