The 44-year-old father of two has not been seen since leaving a riverside bar in the city's port on Saturday night after meeting colleagues.

The club has used their official Twitter and Facebook accounts to appeal for an information about Kraus' whereabouts.

A signal from his mobile phone was last detected on the banks of the Elbe and police are now assuming he could have fallen into the river.

On Tuesday, a police sniffer dog picked up his scent near the water and 100 metres away from the bar where Kraus was last seen.

Hamburg police say a dive team will search the port “as soon as the current and weather conditions allow”.

Police are also eager to speak to the driver of a taxi Kraus got into which took him from the bar to the city centre, before he mysteriously returned to the port around midnight.