Four persons were detained, including the owner of the firm.
Two persons who also were detained are believed to be employed by the security ministry in its department of services for private security firms.
The company is Grupo Seguridad Integral or GSI S.A.
The Judicial Investigating Organization announced the arrests at midday. A release said that two persons in the Dirección de Servicios de Seguridad Privada had been detained by judicial agents on the allegation that they had accepted 35,000 colons or about $68.50 to register individuals as security guards even though some lacked the permit to carry weapons.
The Judicial Investigating Organization did not make clear if the two cases were related.
The security firm case involved the allegation that the purchase of 35 handguns was done in the name of another firm that had no knowledge of the purchase. The original complaint came from the unidentified firm.
GSI is a well-known security firm and even operated armored cars for delivery of cash and valuables. The firm has many employees.