Police said on Thursday they had questioned eight more witnesses in the investigation into the death of TV actress Nida "Tangmo" Patcharaveerapong.
"No theories have been ruled out so far, whether it was an accident or if there was something else behind the incident … we aim to make [the investigation] as thorough as possible with the help of forensic evidence," an officer said.
Among the witnesses grilled on Thursday was Surattanavee "Bow TK" Suviporn, a friend of both Tangmo and her manager.
In total 29 witnesses including four of the five people who accompanied Tangmo on the boat have now been questioned, the officer said.
An analysis of the GPS records is leading investigators to believe the actress fell overboard between 10.29pm and 10.34pm, he said, adding they are now looking into forensic evidence collected from the boat.
The boat was not at the scene when police arrived last Thursday night but police said no evidence is believed to be missing.
The boat was seized from NBC Boat Club in Nonthaburi the following morning.
The superintendent of Nonthaburi's Muang district police station dismissed rumours that the boat's owner recently donated 3 million baht to the station.
"We haven't received the amount claimed and in any case, I insist that everything is being done by the book here."
