Embattled former Democrat deputy leader Prinn Panitchpakdi was on Friday charged with molesting a 26-year-old woman at a condominium, a complaint registered 18 months ago.
Police at Lumpini station laid the new charge against him.
Mr Prinn would not answer reporters’ questions.
Pol Maj Gen Trairong Phewphan, deputy commissioner of the Metropolitan Police Bureau, said the woman had filed her complaint on Nov 13, 2020, the day of the alleged incident.
Police had conducted interrogations and compiled the evdence in the case, he said.
Mr Prinn, 45, faces mutliple charges of alleged sexual molestation, harassment and rape.
There are four cases against him filed at Lumpini station. Interrogators there handled nine of 15 cases brought against him.
One alleged offence occurred overseas and the statute of limitations expired in two cases, Pol Maj Gen Trairong said.
On Thursday Mr Prinn acknowledged a charge of sexual molestation of a 17-year-old female apprentice three years ago. Earlier this week, he was charged with indecency in the northern province of Chiang Mai.
He resigned from all positions in the Democrat Party on April 14, including head of its economic team, to fight the charges, which he denied.
Mr Prinn is the son of Supachai Panitchpakdi, who is a former deputy prime minister, a former director-general of the World Trade Organization and a former secretary-general of the UN Conference on Trade and Development.