Agents investigating the attempted breakout at the La Reforma maximum security unit have encountered an apartment that the Poder Judicial said was to be a resting place for the fugitives once they fled the prison.
The apartment in in San Rafael de Alajuela, the same community in which the La Reforma facilities are located.
The living quarters are in Apartamentos Lidia on a dead end street there.
Investigators found the apartment after following leads from a vehicle, a presumed getaway van, that was parked not far from the prison Wednesday. Agents found money, heavy weapons and explosives in the vehicle.
It appeared that the fugitives were going to try to baffle authorities by leaving the maximum security unit with hostages in a bus and then quickly transferring to the van and then traveling to the apartment.
Seven convicts participated in the armed escape attempt, and an ambush by three tactical squads killed two of them. A prison guard also died in the shootout.
Officials have tightened up security at all the prison locations. At La Reforma there are five separate and independent prisons. There is just one maximum security facility.
Sunday was a heavy visiting day at all the prisons. The prison guard staff was supplemented by Fuerza Pública officers, and visitors had to endure long lines and close inspection.
The maximum security attempt took advantage of woman who were participating in conjugal visits with other inmates. They became hostages, as did members of the prison staff. Although initial theories speculated that visitors brought weapons and fragmentation grenades into the prison for the use of the escapees, more recent investigation has centered on the prison staff.
The Judicial Investigating Organization said he had detained one person linked to the San Rafael apartment. That took place in Limón Sunday.
Agents also are trying to find out who financed the preparations for the attempted escape.
The seven prisoners involved in the escape attempt include Jovel Guillermo Araya Ramírez, a successful escapee in 2006. Araya and Johnny Rodríguez Moya killed a guard when they broke out of prison Oct. 9, 2006, and shot it out with agents when they were caught 15 days later. Araya was wounded six times then. At that time it appeared that someone was waiting for the fugitives in a vehicle nearby. Rodríguez died from bullet wounds Wednesday as did Erlyn Hurtado Martínez, the long surviving bandit from a deadly raid and standoff at the Santa Elena bank near Monteverde in March 2005.