Musician Prachathip Musikapong, son of red-shirt leader Veerakan Musikapong, fell to death from the ninth floor of a condominium in Bangkok late Wednesday.
His body was found on a fourth-floor balcony at about 11.30pm July 29 and a failed love life was believed to be behind the apparent suicide.
Thai media reported that Veerakan Musikapong, a key figure of the United Front for Democracy against Dictatorship, acknowledged at the Thong Lor-area condo that he had lost one of his four sons.
Mr Veerakan said he believed his son jumped to his death because a suicide note was found mentioning problems with a girlfriend. He intended to hold funeral services at Wat That Tong in Bangkok.
Bangkok police chief Sriwara Rangsipramnakul reportedly said police considered the death a suicide as relatives confirmed the handwriting on the note was Prachathip's.
Security-camera footage showed Prachathip entered his apartment alone about 9pm and jumped about 10pm, Pol Lt Gen Sriwara said.
Prachathip, also known as Singha, was a guitarist for Sqweez Animal, a pop, R&B and funk duo that to tour in August.