Public prosecutors have decided to indict Senator Upakit Pachirirangkun with money laundering and a related criminal charge, Kosolwat Inthuchanyong, spokesman of the Office of the Attorney-General, said on Friday.
The decision was made based on an investigation conducted by police investigators who earlier probed Sen Upakit over money laundering and involvement in a transnational criminal organisation.
The senator denies the charges.
On March 17, Sen Upakit, 61, held a press conference to counter allegations made by Move Forward Party MP Rangsiman Rome, who linked him to Myanmar national Tun Min Latt, arrested for drug trafficking last year.
He claimed Mr Rangsiman and some media outlets had come to their own conclusion without backing up their claim. Sen Upakit also denied allegations that he had laundered money from the drug trade through an electricity supply business operating on the Thai-Myanmar border.
Mr Kosolwat said Sen Upakit's case had been handed over to prosecutors. The attorney-general will decide whether to endorse the decision to indict him on July 26.
Under Section 8 of the Prevention and Suppression of Involvement in a Transnational Criminal Organisation Act 2013, any person serving as a member of the House of Representatives, a senator, a local councillor, a civil servant, a state employee, a board member, an executive or manager of a state enterprise, or any person responsible for the operation of a financial institution, or any organisation under the constitution, who commits an offence under this section is liable for twice the normal penalty prescribed for the offence, a source said.