"In that search 13 years ago, it seemed like he just did not want to be found," the 36-year-old Te Puke man said.
"They searched the area but no body was found, just a lot of clothing was found."
Lester Roberts could not comment on if or why his father would fake his own death, but said he wanted his father to come forward.
Lester Roberts has four children, aged 18, 13, 12 and three, who he said never got to know their grandfather. Lester Roberts said he could not remember the last thing he had said to his father but through tears, he described him as a "staunch old fella", but very family orientated.
"He was a loving father."
In light of the sightings, Lester Roberts said his only priority was to be with his family.
Lester Roberts said his father's disappearance had been traumatic.
"I just closed off and just carried on with our lives and keeping my children happy," he said.
Maungatapu man Brian Worth was at Bayfair Shopping Centre in Tauranga five years ago when he believes he saw Mr Roberts. Papamoa man Conrad Carroll said he saw the missing father about two years ago working in overalls on the side of the road in Ellerslie.
Mr Worth said he had worked side by side with Mr Roberts for about three months in 2004 and the two got on well. He said he was convinced he saw him at Bayfair.
"I was walking through Bayfair mall in 2012/2013 and got within three metres of a man talking to a group of people near the food court and instantly recognised him as Bob ... Bob and I locked eyes. Although he didn't change his facial expression, I'm sure he recognised me, but he looked away and kept talking to others in his group."
Mr Worth said he tried to find Mr Roberts on his way back through the food court minutes later, "but he and his group were gone".
"I'm 100 per cent sure it was him. I thought to myself at the time 'he's alive' and then I thought maybe Bob wants to keep a low profile.
"He looked fit and healthy and didn't appear to be homeless or out of sorts," he said.
Mr Worth then checked police missing person reports, but Mr Roberts' photo was no longer there "so I thought the case was done and dusted".
Mr Worth said for years when he and his wife Adrienne drove over the Kaimai Range and passed where Bob's car disappeared they used to yell, "Are you there, Bob?"
"We stopped doing that after I saw him at Bayfair," he said.
"It really rocked me to see him after all those years and some people might think I'm delusional, but I'm not the only one to have seen Bob since he was reported missing."
"I really liked Bob. We really hit it off," he said.
Mr Carroll could not be reached yesterday.