José Armando Urioste, who took office as acting attorney general a week ago, announced the inquiry on Monday. In a letter to the supreme court, he said authorities were gathering evidence against Morales and his former vice-president, Álvaro García Linera, "for the alleged commission of the crimes of murder, abuse, torture and unlawful detention".
The investigation stems from a complaint by rightwing lawmakers Tomasa Yarhui and Rodrigo Antonio. It concerns the raid in Santa Cruz 17 years ago, which killed Eduardo Rózsa Flores, a Bolivian-Croatian, Michael Dwyer, an Irishman, and Árpád Magyarosi, a Hungarian-Romanian. Two others, Mario Tadic and Elöd Tóásó, survived and later reported being tortured after their arrest.
The Morales administration at the time said Rózsa Flores was leading an effort to promote a separatist movement funded by the rightwing economic elite of Santa Cruz. Morales, during an official visit to Venezuela, told the press he had ordered the detention of the foreigners, whom he called "mercenaries".
Victims' families and survivors took the case to the Inter-American Commission on Human Rights, which concluded in 2021 that the government had violated human rights.
Neither Morales nor García Linera has commented on the latest inquiry. Morales, Bolivia's first Indigenous president, is in hiding from two active arrest warrants. One relates to his alleged role in mass protests that paralysed the country for 53 days earlier this year, and the other accuses him of trafficking a minor with whom he is said to have had a daughter. He denies the allegations.