The family of a missing 48-year-old triathlete from Gabon, David Bellet-Brissaud, has offered a R12 000 reward for any concrete evidence on his whereabouts.David Rene Roger Bellet-Brissaud, who was in Port Elizabeth to compete in the Ironman event over the weekend, disappeared from the Paxton Hotel on the beachfront in the early hours of Friday morning.READ: Ironman contestant disappears in the middle of the nightBellet-Brissaud's brother, Gael Bellet-Brissaud, and sister, Vanessa Perret Bellet-Brissaud, both arrived in Port Elizabeth over the weekend to help in the search for their brother. They said they would not leave until he had been found.His daughter Stacey, 21, and son, Anthony, 18, are with their grandmother in Paris.Speaking to the media on Monday, his wife, Lydia, said she and her husband had arrived at the hotel shortly after 15:00 on Thursday last week, had checked in and then went down to Hobie Beach, to look at the starting line for the event."We then went for dinner with friends, who were also from Gabon, at an Italian restaurant at the Boardwalk, before we went back to the hotel," she said,Lydia said her husband had gone to the room, while she stayed downstairs with friends, before also retiring to their room at around 23:00.She said she woke up at around 01:20 and realised that her husband was not in the room."I thought he had maybe gone outside for fresh air," she said.'Quiet' before disappearanceLydia said when he did not return, she had gone to the reception to ask for him. She said she then woke her friend and his wife, who were also staying at the hotel, to help look for him.She said when they did not find him around the hotel they had taken the car and driven around to look for him. They then decided to call the police at around 03:00.Lydia said her husband had not been himself and had been very quiet before his disappearance. She said she had attributed it to stress in the build up to the competition. She said it was the first time that he had gone out on his own like that, and that they were aware of the reputation that South Africa had as a high-crime area.Gael said while his brother had left his cellphone in the room, he had been wearing a Garmin fitness tracker. He said they were still trying to activate the tracker's GPS to determine its location.He said it was not possible that his brother had gone out on his bike, as it had only arrived by plane the following day.CCTV footage showed that David had been wearing a black Adidas hoodie top, blue jeans and takkies when he left the hotel.Members urged to help policeHis sister Vanessa, who at one point broke down and had to leave the venue, described her brother as "an ordinary guy"."He doesn't smoke or drink. He is not a man with enemies and he worked at the same forestry company for the last 15 years," she said.Vanessa thanked the police and the staff at the hotel for their ongoing support."They have been very helpful and supportive," she said.Police spokesperson Colonel Priscilla Naidu confirmed that Bellet-Brissaud was still missing."Police are urging businesses along the beachfront to view their CCTV footage and see if any person fitting the description of Bellet-Brissaud may be picked up on their cameras while he may have been walking past," she said.Naidu said the police's K9 unit, SAPS airwing and divers had scouted the entire beachfront area in an attempt to trace him. "Police are appealing to the public to communicate any information, no matter how insignificant it may seem, to the investigating officers detective Warrant Officer Eric Mathews on 083 380 3714, detective Constable Ridwaan Baatjies on 073 130 3018 or via Crime Stop on 08600 10111.She said they could also contact the Humewood police station on 041 504 5019.