The governor of Mexico’s Puebla state, Martha Erika Alonso and her senator husband, Rafael Moreno, were killed in a helicopter crash near the city of Puebla on Monday, reported Reuters. She took oath on December 14.

Two pilots also died in the crash, while a fifth passenger was also presumed to be on board.

The Agusta 109 helicopter crashed about 10 minutes after taking off from a heliport in the city of Puebla, AP reported. Security Minister Alfonso Durazo said the privately-owned helicopter was bound for Mexico City and crashed after suffering an unspecified failure. “At this point, there’s no evidence that could lead us to conclude that the cause was not related to how the [helicopter] was functioning,” Durazo said.

Alonso, who was a member of the National Action Party, was sworn in as governor on December 14 after narrowly beating Manuel Barbosa, who was the Mexican president’s favoured candidate. President Andrés Manuel López Obrador alleged irregularities in the elections, following which an election tribunal validated the poll result for Puebla.

Obrador said his government would launch an investigation into the incident to find “the truth” about what caused the crash, BBC reported.

Former Mexican President Vicente Fox, who has been a critic of Obrador, said he was troubled by the timing of the accident after the electoral dispute. “Every single doubt must be cleared up,” he said.