Judicial agents detained three men and a woman Thursday and linked them to 25 home invasions.
The armed home invasions were reported to have taken place in San José, Cartago, Heredia, Alajuela and Grecia.
Four other persons who are linked to the same crimes are already under arrest, said the Judicial Investigating Organization.
Home invasions, when bandits burst into an occupied home, are a continuing concern of expats, although Costa Ricans victims are more numerous.
Judicial agents engineered 11 raids Thursday in Purral de Goicoechea, Coronado, Moravia and Cartago, said the Poder Judicial.
Those arrested were identified by the last names of Goñi, a 36-year-old woman, Serrano, Brenes and Pizarro, the men whose ages ranged from 21 to 30.
The four persons detained earlier were captured after a home invasion took place May 14 in Turrúcares de Alajuela, agents said.
Residents there were tied up.
The gang that has been the focus of the judicial investigation spent time planning their invasions. They kept watch on various homes to determine the best time to commit the crimes, agents said.
Sometimes they would spend as much as 11 hours inside the home, threatening the occupants to surrender the credit cards and ATM codes.
Some members of the gang would leave to access the bank accounts of the victims at automatic tellers, agents said.
Investigators said they recovered items that had been stolen in their searches Thursday.