The Mexican government is demanding what it calls an “extensive and prompt” investigation into the suspected killings of two men and one boy from Mexico in Phoenix.

The bodies of the three migrants from the southern state of Oaxaca were found in a vacant lot in west Phoenix with clear signs of trauma in late February, according to officials.

On Wednesday, President Andrés Manuel López Obrador said that the head of the country’s foreign ministry, Marcelo Ebrard has called on the U.S. to fully investigate the case to determine whether the victims — ages 16, 21 and 28 — had been tortured and murdered while in Arizona.

The president said the foreign ministry and consulate in Phoenix would be in close contact with police as they carry out a homicide investigation.

The consulate also said in a press release that it will assist in returning the bodies of the victims to their families in Mexico.