The Police Merit System Protection Board has voted to support the directive removing former deputy national police chief Pol Gen Surachate Hakparn from office.
The six-member board unanimously agreed that the Royal Thai Police Office order dated April 18 dismissing the deputy police chief was legal and valid and appropriate.
The board voted after 10 hours of debate on Monday. Pol Gen Surachate had petitioned the panel to revoke his marching orders.
It was another defeat for the embattled police general, who is being investigated for alleged links to online gambling, which he denies. The 12-member Police Commission voted unanimously in July in support of his removal.
Pol Gen Surachate's sacking still requires royal endorsement to become effective. It must be forwarded to HM the King by Prime Minister Srettha Thavisin.
Until then, Pol Gen Surachate is still free to fight his case and can ask the Supreme Administrative Court to protect him from the dismissal order.
The suspended deputy police chief could not be reached for comment, but he had said earlier that if the panel's decision was not in his favour, he would consider taking the case to the court.
Pol Gen Surachate was among the frontrunners to succeed national police chief Pol Gen Torsak Sukvimol when he retires at the end of September this year. The directive removing him from office puts his future in doubt.