Prosecutors released Future Forward Party leader Thanathorn Juangroongruangkit and other party executives on Wednesday after police charged them with computer crimes.
Prosecutors said they will decide on the indictment on March 26 - two days after the general election.
Technology crime suppression police took Mr Thanathorn, his party registrar Klaikong Waithayakan and party executive member Jaruwan Saranket to the Office of the Attorney-General (OAG) on Ratchadaphisek Road on Wednesday morning.
They asked the state prosecutors to indict them on charges of putting false information into a computer system.
The charges relate to an accusation made on Facebook live sessions last year that the National Council for Peace and Order had poached former MPs from their various parties.
Wichian Thanompichai, OAG executive director for criminal litigation, said a working group would spend a month considering the case. Mr Thanathorn and the two others were ordered to report again on March 26 to hear the decision on whether they would be indicted.
In the meantime, they were free to go because they had no intention to flee, he said.
Mr Wichian said officials were not speeding up the case. The NCPO had filed its complaints last July. The case had attracted public interest and would be handled fairly.
Mr Thanathorn told reporters on Wednesday his party was gaining popularity, so there were attempts to block it.
In an exclusive interview with the Bangkok Post, Mr Thanathorn said he was "not worried at all" about the charges. "Article 14 of the Computer Crime Act stipulates...that if you upload false information...that causes public panic you can be charged," he said. "First of all it was not false information, it was public information that was circulated by many media organisations. Secondly, it caused no-one panic.
"It is clear that this charge is politically motivated," he said. "This charge will have no effect."
Mr Thanathorn and the two party executives face a legal complaint filed by the NCPO in connection with remarks they made live via two Facebook pages, "The Future We Want" and "Thanathorn Juangroongruangkit", on June 26 last year.
They claimed the NCPO was poaching former MPs. At the time, politicians with a strong chance of election were reportedly planning to eventually defect to the pro-regime Palang Pracharath Party (PPP).
Later, Col Burin Thongprapai, representing the NCPO, filed a complaint with police against Mr Thanathorn and the two FFP executive members, insisting the remarks were untrue.
Many former MPs later defected to the Palang Pracharat Party.
FFP spokeswoman Phannika Wanit said on Tuesday the party was not worried by the poaching lawsuit brought by the NCPO.
"The issue has been widely talked about, and if anyone or party was to be prosecuted over it, every single person in this country would go to court," she said.