The International Press Institute (IPI) on Wednesday expressed concern at the death of a Bolivian journalist who was killed by an explosive device which caused deadly injuries to his abdomen.

David Niño de Guzman, news director of the Agencia de Noticias Fides in La Paz, was found dead 21 April on the shores of the Orkojahuira River in the Retamanis neighbourhood of La Paz, two days after he disappeared after receiving a telephone call.

According to news reports, the incident was being looked into by the special investigative unit of the Bolivian police, which had three possible theories: homicide, a “settling of scores” or suicide. A spokesperson for the unit claimed that it had found dynamite and blasting caps in Niño de Guzman’s home, but that authorities had not established how the explosives got there.

However, Niño de Guzman’s wife, Sandra Flores, maintained that her husband was assassinated. She said Niño de Guzman did not like any type of arms, and that he had been anxious in the days leading up to his death.

IPI Director Alison Bethel McKenzie said: “IPI mourns the sudden and violent loss of David Niño de Guzman. We demand that the authorities carry out a thorough investigation and bring the perpetrators to justice.”

Niño de Guzman, 42, had worked for a number of media organizations in a journalism career spanning 16 years, including La Razón and El Diario.

Bolivian press organizations have called on the authorities to investigate Niño de Guzman’s death, arguing that it was possibly linked to his work.