Doc Wakatipu area manager Greg Lind said the department had gone as far as it could and it was ''now a police matter''.
The word ''Rowdy'' had been written using a large marker pen on items along the 32km Routeburn Track about April 19 or 20.
The offender appeared to have walked from the Glenorchy end of the track to The Divide.
The same tag had appeared at the Wanaka skate park, the Franz Josef Glacier access area and in Tuatapere.
Yesterday the Otago Daily Times received an email from a Wellington resident who reported seeing the tag on a residential walkway joining the top of Oriental Terrace (Oriental Bay) and Hawker St.
Mr Lind said between April 19 and 20 about 100 people walked the Routeburn Track and Doc had managed to speak to all but one of the leads, a group of backpackers.
''[They] may just be moving around the countryside, but that's the only line of inquiry at the moment.
''It will either give the police something to follow up on ... or not; they maybe completely innocent.''
