In a fresh twist to Karl Slym's death in mysterious circumstances, police said the three-page handwritten note found in the hotel room from which the 51-year-old executive plunged to his death, was written by his wife Sally.
Police said Karl Slym could have taken the "extreme step" after reading the note by his wife of 30 years that mentioned "domestic problems".
"The note was written by Sally Slym. The couple had had an argument. It is her writing," Police Lieutenant Somyot Booyakaew said, noting that it was not a suicide note by the victim. He did not give further details.
Somyot reiterated that Karl Slym's death was not a murder.
Police now believe Slym must have jumped through an open window in his 22nd floor suite at the Shangri-la Hotel as the opening was too small for a person to slip through and fall.
The suite has a huge sealed window overlooking the Chao Praya River and a small nearby window that can be opened.
Slym died from the impact of the fall, which fractured his skull. The British national's body was found on Sunday by the staff of the 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 Slym' room, which did not have a balcony.
Police said yesterday that they were translating the note into Thai language as part of the investigation.
Sally was with Karl Slym in the suite and was woken by hotel staff on Sunday morning after they found his body. She has been in a state of shock since the incident.
Karl Slym was leading Tata Motors at a time when the auto industry was grappling with a prolonged slowdown.
He joined the auto major in 2012 as part of a major management overhaul and was responsible for charting the company's strategy to regain momentum in the Indian market.
Expressing condolences at the sudden demise, Tata Motors Chairman Cyrus P Mistry said: "Karl (Slym) joined us in October 2012, and was a valued colleague who was providing strong leadership at a challenging time for the Indian auto industry. In this hour of grief, our thoughts are with Karl's wife and family."
Before joining Tata Motors, Slym was the executive vice president, SGMW Motors, China (a General Motors joint venture). Prior to that, he was president, managing director and board member of General Motors in India during 2007-11.
For over two decades, Slym was with Toyota and General Motors in various positions across geographies.