The note mentioned "domestic problems", Police Lieutenant Somyot Booyakaew said.
"The letter was written by Karl Slym's wife about domestic problems," Somyot told PTI, adding that Slym's death was not a murder.
Also Read
51-year-old Slym's body was found on Sunday by the staff of the riverside Shangri-la Hotel on the balcony of the fourth floor after plunging from the 22nd floor.
He was here to attend a meeting of the Board of Directors of the Thai subsidiary of his company.
Somyot earlier said there were no signs of a struggle in the British national's room, which did not have a balcony but had a big sealed glass window and another smaller window that could be opened.
The room has a big sealed window overlooking the Chao Praya River and a smaller window which could be opened nearby.
)