"According to our investigation, you're not the poor fellow you present yourself as," Rayo says sharply. He then runs through a list of assets that include nine hectares of land dedicated to growing coca, the raw material for cocaine. Long known for their collusion in the drug trade, the rebels know just how much the crop is worth.
After a clipped discussion, the farmer agrees to up his child support payment to $52 a month, from the previous $40.
It is scenes like this one, played out in Colombia's southern demilitarised zone, that have international human rights organisations worried about the well-being of residents. Meant as a goodwill gesture leading into peace talks, the government cleared its troops from the zone a year ago, leaving an area twice the size of Wales in the hands of the Revolutionary Armed Forces of Colombia FARC.
But as peace talks with the FARC lurch forward, many think the government has abandoned the zone's 97,000 inhabitants to a dangerous rebel army. The FARC is already known for its rampant kidnappings of civilians, and in March it admitted to the murder of three US indigenous rights workers.
"There is a vacuum in the administration of justice," said Carlos Salinas, Latin American advocacy director for Amnesty International. "We do not believe that the FARC has the capacity or the legal standing to supply such a service."
Amnesty recently sent a delegation to monitor the situation in the zone and to query 14 alleged executions. The FARC admitted to six killings.
"We didn't ask for this. We didn't request it. They [the government] didn't inform us about it," said Edwin Alberto Valdez, the acting mayor of San Vicente, one of the zone's larger towns.
Valdez said banks and insurance companies were steering clear of the area, and that families were sending their teenage children away, possibly to avoid being pressed into rebel ranks.
On the other hand, violent deaths have declined substantially since the FARC took control. San Vicente's hospital registered 95 violent deaths last year, most of them the result of fighting between leftist rebels and right-wing paramilitaries. So far in 1999, there have been 25.
In a poignant reminder of officials' precarious role here, Valdez's predecessor left two months ago for a sabbatical in Europe after he received death threats, one from the head of Colombia's paramilitary organisation. The mayor of Vista Hermosa, another town in the zone, was shot to death in October.
Meanwhile, local press reports insist the FARC are bulking up militarily in the zone by stockpiling arms, training troops and recruiting minors.
Such allegations have become all the more disturbing since the ELN, the country's second largest guerrilla group, is also asking for a demilitarised area as a prerequisite to peace talks. For its part, the FARC acknowledged making mistakes in its new administrative role, but insisted it had asked for the zone to create a safe place for dialogue, not to impose martial law.