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The German family of a Bay of Plenty man who disappeared in February have asked Interpol to look into police handling of the matter.
Sigfried Newman, 49, disappeared on February 25 after dropping his two sons at school.
Tauranga police searched for three days but found no sign of him.
At the time, police said it was believed Mr Newman was struggling to cope with the death of his wife late last year.
Mr Newman's family told the Bay of Plenty Times they were convinced their brother was dead and that foul play was probably involved.
