Pekanbaru. A Thai woman has been detained after attempting to illegally apply for an Indonesian passport using falsified documents. Her mother, who visited her a few days later, was also charged with immigration offenses, authorities said on Thursday.

The woman, identified by her initials JJ, was arrested on October 2 when she appeared at the immigration office in Dumai, Riau Province, for an interview related to her passport application.

JJ had submitted what appeared to be legitimate Indonesian citizenship documents, including an ID card, birth certificate, and family certificate issued by the Dumai government.

However, during the interview, officials became suspicious due to her language difficulties and asked her basic questions about the national anthem and Indonesia’s national ideology.

"JJ was unable to answer any of the questions and later admitted that she is a Thai national," said Budi Argap Situngkir, head of the Riau Justice Department.

"The documents seemed valid and met all the formal requirements, but during the interview, her lack of basic knowledge about Indonesia raised our suspicions," Budi explained during a press conference in Pekanbaru, the provincial capital.

Budi added that JJ is allegedly wanted by Thai law enforcement authorities for a crime and had attempted to hide in Indonesia.

Both JJ and her mother, identified by the initials TK, entered Indonesia illegally via speedboat from the Malaysian state of Johor, arriving on Batam Island on September 29.

A few days after JJ’s arrest, her mother visited her at the immigration detention center, where she too was detained for document forgery and illegal entry.

The charges against them carry a maximum sentence of five years in prison and a fine of up to Rp 500 million ($32,219).

The two women will be transferred to the Justice Ministry in Jakarta for further investigation and coordination with the Thai embassy, according to Budi.

The immigration office is working closely with the police to identify local accomplices who provided the women with the falsified Indonesian citizenship documents.

"This is a serious act of treason against Indonesia," Budi said.