A police officer in Puerto Rico was arrested Monday after he shot and killed three fellow officers at a police headquarters, investigators said.

CNN reports the officer is in police custody for allegedly gunning down a police commander, a lieutenant and an officer at a station in the southern coastal city of Ponce.

Puerto Rican news outlet El Vocero, identified the suspect as 50-year-old Guarionex Candelario.

The victims were said to be female Lt. Luz M. Soto Segarra, 49, male Cmdr. Frank Roman, 49, and policewoman Rosario Hernández de Hoyos, 42.

Puerto Rico Police Deputy Superintendent Col. Juan Rodriguez Davila released a statement on the police force's Twitter page.

"There are no words to describe this tragedy where three colleagues have lost their lives. Our condolences for the families," read the translated statement.

According to The Associated Press, the suspect held the three victims hostage in an office before killing them. Authorities attempted to negotiate with Candelario to no avail.

Investigators are uncertain about Candelario's motives, although reports say the incident occurred after an argument at the police station.

Authorities said they evacuated the station due to threats of potential explosive device stored in the suspect's vehicle. It is unconfirmed if any evidence was found.

Police spokeswoman Mayra Ayala told The Associated Press that Candelario worked in the department's anti-drug division.

Jose Cruz Martinez, vice president of the Puerto Rican Police Union, said victims Soto and Roman were longtime friends of his who had been working with Puerto Rico's police department for over 20 years.

Soto lived the nearby town of Yauco, while former Commander of the Year Roman hailed from the western town of Mayaguez.

"They were both excellent people," Cruz said. "They were always supportive of their coworkers."

Mayor Maria Melendez of Ponce, Puerto Rico's second largest municipality, said the city was in a state of mourning.

"May God give the family members of the police officers involved the strength, fortitude and serenity to absorb this news," she said in a statement.