State Police received information about the planned contract killing in January and had now collected enough evidence to request British authorities to arrest the woman.
LETA reports the police as saying the woman is a factory worker in the United Kingdom.
Investigators say the motives were personal rather than tied to the official's status. The official hadn't received threats prior to the incident.
"We've succeeded in preventing a contract killing in its preparatory stage and arrested the person who ordered the killing. There was a €1,200 reward promised in return for the murder," said police representative Romāns Jašins.
The police did not name the official in question.
The woman is under arrest and officials are handling her extradition.