Investigators detained 11 men Tuesday in three separate murder cases, including one where the victim was buried on Playa Palo Seco in the central Pacific.
In addition, Ministerio de Seguridad Pública officers raided an isolated camp they said had been used as a support base for drug helicopters.
Judicial police detained three murder suspects during 5 a.m. raids of three homes in Finca San Juan de Pavas They are accused of killing a man with the last name of Chavarría in a drug dispute last July 7 in the same area. The suspects range in age from 21 to 32.
Investigators said they found a bulletproof police vest, crack, cash and other evidence.
In another case, four men were detained in various locations in an investigation of the murder of a 44-year-old man with the last name of Ramírez. That crime took place May 16, 2014.
Agents described the four, who ranged in age from 37 to 52, as the intellectual authors of the killing.
Agents said that the victim was eating with one of the men at a Cartago restaurant when two men on a motorcycle drove up and one of them fired the fatal shots.
Arrests were made in Tres Riós, Nicoya and in Granadilla in Curridabat. Agents said that this killing also was related to drugs.
The murder of a man with the last name of Parra was more recent.
The body of the 33-year-old man turned up bound hands and feet in a grave on the Palo Seco beach near Parrita Sunday.
Police quickly linked the case to four men who were detained in five raids at Reformadores de Parrita at 6 a.m. The men range in age from 18 to 48.
Agents stopped short of calling this a drug-related crime, but they did say the motive appears to be some sort of revenge.
An informal source said that Parra met his death in one of the homes that had been raided and that agents had used luminol to find traces of blood.
Security ministry officers said they had to hike three hours in Suerre, Jiménez, Pococí, Limón, to reach the site of the suspected helicopter landing base.
The site that included a frame building had been abandoned. When in use, the buildings had been camouflaged by plastic sheets to defeat discovery from the sky, said police.
Officers from the Policía de Control de Drogas, the Fuerza Pública and from the Servicio de Vigilancia Aérea were involved in the raid.
They said the land owner did not know about the camp.
Police surmise that the camp was used as a rest stop for helicopters transporting drugs from the Limón coast to the northern zone and Nicaragua.