Amarat Chokepamitkul, a list-MP of the opposition Move Forward Party (MFP), is expected to meet investigators from Nang Loeng police on Tuesday in a defamation case brought against her by the government.
In a complaint lodged with Nang Loeng police by Aphiwat Khanthong who is a member of the government's team monitoring information spread on social media against the PM and other cabinet ministers, Ms Amarat is accused of defaming Prime Minister Prayut Chan-o-cha in a tweeted message, said the source.
Tweeted on her own Twitter account on May 8, last year, Ms Amarat's message portrayed the PM as a "thieving PM" who provided protection to a drug mule.
It also said the PM had robbed his premiership from someone, said the source.
In the tweet, she also dared the PM to take legal action against her for what she had just tweeted.
On Oct 27 Pol Lt Co Nitithon Tatichayanon, deputy chief of the station's investigation section, submitted to the South Bangkok Criminal Court a request for an arrest warrant for Ms Amarat in relation to the case.
It is not yet known if the requested arrest warrant was approved.