Volunteers have been out all weekend searching for missing autistic man Nigel Peterson, a process which has been emotionally draining for his family.
The search for Nigel, who went missing on November 17 last year, was reopened after extensive scientific research revealed new information.
A city and district-wide search failed to find him at the time of his disappearance.
A three-day search began on Friday, focusing on bush, scrub and waterway areas at the Rotorua Golf Club and Arikikapakapa Reserve.
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Nigel's father Chris Peterson said he and family had come over to Rotorua on Saturday morning so they could be a part of the search in some way.
He said they were taken into the police station and informed about what was going on.
They discussed where they were targeting as the highest probability areas and kept them in the loop, he said.
"They are very good to us, they keep us quite involved and knowing what's going on.
"It's a wonderful group of volunteers, as well as the police. They've gone out in some terrible weather and done their best for us. We appreciate what they've done for us."
Peterson said they were heading back to Whakatane late this afternoon.He said Nigel's little sisters had also come over so that they felt like they were part of what was going on and saw what was being done.
"They will have to process this in later life."
Peterson said it was emotionally draining to be in this situation.
"It is very tough when you had quite a bit of expectation going into this weekend."
He said there had been some good targeted searches which he thought had some promise but there had been no luck.
"It's still pretty gut-wrenching. We appreciate what the volunteers have done for us, but it's pretty hard to deal with the situation at the moment, but we've got to carry on."
Rotorua police Constable John Fredericksen said they had made good ground but had not come across anything useful yet.
The weekend's search included the area around Highland Loop Rd.
He said there was a fantastic turn out by the LandSAR volunteers, with about 18 searching on Saturday, along with two police to help.
Fredericksen said the area of the search was physically hard going, including some scrub, blackberry and gorse.
"It's wet but it's a pretty dedicated bunch. There are fantastic volunteers out there."