The investigation stems from when Luis Arce was minister of economy under then-president Evo Morales.
Ex-President Evo Morales is under investigation for alleged statutory rape and human trafficking, which he denies.
Supporters of Evo Morales have clashed with followers of his rival ahead of 2025 election
The discovery comes at a time when gas exports - one of Bolivia's main sources of revenue - had dwindled.
Followers of President Luis Arce and former president Evo Morales faced off in La Paz.
It all started when the presidential palace in La Paz was stormed by soldiers.
Jeanine Áñez is sentenced to 10 years in jail in a case she says is politically motivated.
