"After fully exploiting the possibility of establishing the whereabouts of Venckienė and present her with summons, Šiauliai prosecutors decided to call a search," Šiauliai Prosecutor's Office said in a press release.
Police have been authorized to establish the MP's place of residence.
Šiauliai prosecutor had authorized police officers to present Venckienė with summons to testify in a criminal case, but the authorities failed to find her.
On Friday, the police of Kaunas, the second-biggest city of Lithuania, have asked to launch international search for Venckienė.
Kaunas County Chief Commissariat has sent related documents to the International Relations Board of the Lithuanian Criminal Police Bureau, the police has said on Friday.
Venckienė has been missing since parliament stripped her off her legal immunity on April 9. Since then, she has not appeared at the parliament sessions and has been beyond reach of the police.
Members of the Path of Courage parliamentary group maintain they are not aware of Venckienė's whereabouts. MP Valdas Vasiliauskas, a member of the group, said Venckienė is in the United States and may apply for political asylum there.
Last October, prosecutors brought suspicions against Venckienė on six counts of the Criminal Code. She is suspected of publicly disrespecting court, failing to execute a court order to hand over her niece to the girl's mother Laimutė Stankūnaitė, impeding a bailiff from executing a court order, abusing her rights as a child's representative, physically resisting a police officer, and causing minor injuries to Stankūnaitė.
Elected to parliament last fall, Venckienė acquired legal immunity, which she lost in April this year.
Between October 2009 and May 2012, Venckienė was appointed the guardian of the daughter of her late brother Drąsius Kedys and his girlfriend Stankūnaitė. The girl was handed over to the mother on May 17 last year with the help of large police assistance.
Kedys had accused Stankūnaitė of prostituting their small daughter to pedophiles. However, no suspicions were brought against Stankūnaitė, and a court cleared the only suspect, Andrius Ūsas, of all charges.
