Lynne Bean, who last heard from her son, Brett, almost two weeks ago, is expected to offer a reward tomorrow for information about his whereabouts at a media briefing at the new Karon police station, on Phuket's holiday west coast..
''He's a man of routine, that's why this is so strange,'' said Naomi Smith, a friend of Brett's who is travelling with Mrs Bean.
The two women were interviewed by police in Karon this afternoon with the help of interpreter Ananya Insumran.
Brett, who has been coming to Phuket for the surf season for at least five years, last contacted his mother by email on November 26, saying he was about to join friends for lunch.
He was due to fly to Los Angeles via Hong Kong on November 27, but his parents began to worry when he failed to arrive.
Inquires revealed he never checked in for the first leg of his flight, from Phuket to Bangkok, or subsequent flights.
The 43-year-old was last seen in person by a neighbor the previous weekend. He was riding his motorbike - a silvery grey Honda 125 cc - down a hill near his home in Kata-Karon.
Mrs Bean does not like to pry into her son's private life so has little information about Brett's social circles on Phuket. She is keen to talk to his friends.
Police found his rented bungalow in the Kata-Karon area ''neat and clean,'' said Denny Bowman, a US Embassy Warden on Phuket.
''Everything was in order: the door was locked, his clothes were on the line out the front, the trash had been taken out, and there were no dirty dishes.''
On a shelf in Brett's bungalow, a Phuket English-language newspaper clipping about a theft in the area in August was found. It's not known whether there is any connection between the clipping and Brett's disappearance.
Mr Bowman accompanied Mrs Bean and Ms Smith to see the bungalow last night, with a group of detectives. The second visit to the bungalow by police indicates that their investigation is growing more intense.
''There were no worrying signs,'' Mr Bowman said today about the check on the bungalow.
Brett, who kept in regular contact with his mother, had told her that friends would be able to reach her if anything ever happened to him.
Mrs Bean and Ms Smith worry that because Brett was due to leave Phuket, many of his surfing friends may have also left Phuket for other destinations and not yet know of his disappearance.
Another friend of Mr Bean's on Phuket has also said she is ''99 percent certain'' she saw Mr Bean riding along the beach road in Karon on December 1.
Members of the Aspen ski school where Brett was due to join Ms Smith as an instructor this month are wearing ribbons to show their support.
''In Aspen he works almost every day, saving up money to come back to Thailand,'' Ms Smith said.
The statement that Mrs Bean gave police today will allow them to access Brett's mobile telephone records.
''The police and so many people have been so helpful,'' Ms Smith said.
Mrs Bean and Ms Smith will begin handing out missing person flyers in the area where Brett lived from Monday.
Brett is 6 feet 2 inches tall, slender, and has blond hair and blue eyes. He has two tattoos - one on his left forearm and one of a snake on his right thigh.
He sometimes grows a beard and at other times goes clean-shaven.
Mrs Bean and her husband Wayne moved from South Africa to the US in the 1960s.
Anyone who thinks they might have seen Brett should contact the US Embassy in Bangkok on 02 2054049 or after hours on 02 2054000, or write to Phuketwan via the comments space at the end of this article.