Germany's federal prosecutor is checking whether he should take over the investigation into a fatal stabbing in Hamburg earlier this month.

A spokesman for the prosecutor's office told German news agency dpa on Sunday they're looking into the case following a statement by the IS-run Aamaq news agency on Saturday saying "a soldier of the Islamic State" stabbed two people in Hamburg on Oct. 16.

Two teenagers were sitting on the waterside of a Hamburg lake that day, when a man approached them from behind, stabbed one of them with a knife and pushed the other one into the water.

Different from the IS claim, only one person was fatally stabbed. The other one who was pushed into the lake was rescued.

Hamburg police are still looking for the attacker.