BOGOTA (Reuters) - Marcelo Pecci, a Paraguayan prosecutor known for his work in fighting organized crime, was killed on the Colombian tourism island of Baru on Tuesday, authorities from both countries said.

       Pecci and his wife, Paraguayan journalist Claudia Aguilera, were on their honeymoon at a resort near the Caribbean city of Cartagena. They had announced Aguilera's pregnancy on Instagram earlier on Tuesday.

       Aguilera told Paraguayan media the couple were approached by two men on a private beach connected to their hotel before her husband was shot. He had not received threats, she added.

       Pecci, 45, was known for his work on high-profile anti-money laundering and anti-drug cases, the investigation into the murder of a regional governor's daughter last year and the case against Brazilian footballer Ronaldinho, who was arrested trying to enter Paraguay with adulterated Paraguayan passport in 2020.

       A delegation of Paraguayan police will arrive shortly to join the investigation, Colombia's national police chief General Jorge Luis Vargas said.

       "We have information that is being collected in urgent efforts and which is confidential which will help us to identify those responsible for this regrettable occurrence," Vargas said.

       Officials from the United States will also aid the investigation, he said.

       "The cowardly assassination of the prosecutor Marcelo Pecci in Colombia saddens all of the Paraguayan nation," Paraguayan President Marcelo Abdo said on Twitter. "We condemn in the most energetic terms this tragic occurrence and redouble our commitment in the fight against organized crime."

       (Reporting by Julia Symmes Cobb, additional reporting by Nicolas Misculin in Buenos Aires and Daniela Desantis in Asuncion; Editing by Angus MacSwan)