German authorities are investigating a threat of an attack on the justice ministry, reportedly by a team linked to Al Qaeda, the ministry said yesterday.A ministry spokeswoman said its staff had been put on the alert following the warning, which press reports said had been telephoned to the Lebanese embassy in Berlin. Lebanese police had arrested the caller, named as Syrian Mohammed Ndoub, alleged to have links to Al Qeada and the Islamic Jihad movement. Ndoub said that a three-man squad, comprising a German of Turkish origin, a Saudi and an Australian, were in Germany with the intention of attacking the targets in Berlin.