The killings happened overnight in an isolated part of the Jamundi municipality in southwestern Colombia and also left two vehicles incinerated, officials said. It was the third massacre in Jamundi in the past year.
Authorities said two of the bodies were found under a bullet-riddled vehicle while three were located farther up a dirt road. All five had to be carried by horse to a nearby school and then flown by helicopter to a morgue, due to both dangerous conditions in the area and a lack of reliable roads.
Manuel Antonio Vásquez, commander of the Cali metropolitan police, said investigators believe the bloodshed stemmed from a conflict among illegal armed groups, with one criminal band suspecting that the victims were either from a rival gang competing for drug territory or a team of state investigators working in the region.
An estimated 230 soldiers were dispatched to the area in response.
"We are here guaranteeing the security of inhabitants," Vásquez said.
Local officials urged the national government to build better roads, provide basic services like security, health care and education and help substitute coca crops as a means of rooting out illegal armed groups. There are an estimated 1,000 hectares (2,470 acres) of illicit crops in the area.
"We need to confront this with a greater institutional presence," Jamundi Mayor Andrés Felipe Ramírez said after the killings.
Last January, four members of a Jamundi farm family that cultivated crops like bananas and yucca were found shot to death, authorities told local media at the time. In October, four people were killed in a different part of Jamundi in an attack attributed to dissident rebels.
Colombia's biggest rebel movement signed a peace agreement in 2016 to end over five decades of conflict, but remnant armed groups are still wreaking havoc in parts of the country with bountiful drug crops and little state presence.
Renegade fighters from the disbanded Revolutionary Armed Forces of Colombia operate in the area and some officials voiced suspicion that they were involved in the attack.
On Monday, Carlos Ruiz, who heads the U.N. Verification Mission in Colombia, told the U.N. Security Council that "significant strides" have been made in implementing the peace deal but noted that continuing violence in conflict-affected regions remains a threat.
He pointed to "profoundly worrying" developments in recent weeks, including territorial disputes between illegal armed groups that risk spreading into more widespread violence.