He estimates hundreds of local people took part, driving and walking streets searching, including a group of teenagers who checked schools.
"The response on Facebook and through the media was incredible. It's such a good tool ... there were lots of people out searching. Neighbours ringing people in the area. There were a lot of people searching. It was wonderful ... It's been such a great response," he said. "It's a great result for the family."
People with Alzheimers behave in a particular way and generally travel in the same direction until they hit a barrier. Mr Cunningham said, as a result of sightings of her heading south on Chapel St, the search was centred south of the retirement village.
The first sighting of Dr Roberts was on Cornwall St just after 2pm and on Chapel St a short time later when a policeman saw her heading south outside Pak'n Save.
Five teams headed out knocking on doors and asking permission to search sections.
A helicopter checked schools, drains and waterways from the air until light faded.
Concerns were then heightened about 2.30am when a front, bringing cold, wet weather settled in.
"The temperature dropped and we were quite concerned at this point. We were worried because there had been no more sightings of her ... we were hoping she was tucked up somewhere."
Much to their delight, she was found asleep in the laundry of a house right next door to Metlifecare and taken to hospital to be checked out.
"We were elated ... she is safe and well," Mr Cunningham said. "I couldn't wait to tell her daughter."
Earlier, searchers had not found anyone home and were heading back when she was found by the owner.
Senior Constable Tony Matheson said he was also impressed with the community support. As residents heard the helicopter, they came outside to help look for her.
"The response from the public was incredible," he said.
LandSAR member and WaiCol teacher Kath Wilkie helped search until just after midnight and said it was awesome to see the community out in force. "It was terrific."
Fellow LandSAR member Lee McKinstry said there was always a sense of urgency in finding missing people; especially when someone was frail, elderly and possibly confused. "It's fantastic she has been found alive."
He's also stoked with the community help. "It reinforces what you are there for."
Meanwhile, another man who helped search and didn't wish to be named said he was concerned to find another elderly person had wandered off from the retirement village.
He said he had picked up a confused man with dementia from outside the village about a year ago and guided him back.
His concern was staff could have found Mrs Roberts sooner had they searched neighbouring properties.
"How can they not have looked next door? They should have checked. It's a bit slack. They should have checked the sheds of homes next door. They'd have found her."
Metlifecare did not respond to calls from the Times-Age.
