The cold-blooded murder has shocked Spain and initiated debate over the need for tighter gun control.
Ismael Rodríguez, 28, was arrested on Saturday after turning himself in for the shooting of the two guards.
David Iglesias, 39 and the father of a seven-year-old girl and Xavier Ribes, 39, the father of a ten-year-old boy, both died at the scene after approaching Rodríguez and asking him to show his paperwork.
The perpetrator had a weapons licence but not for the shotgun he was carrying, according to Catalonia's regional Interior Minister.
"He did have a valid type D permit but it was the (Tyoe E) one required for the 12-gauge shotgun he was carrying,” Jordi Jané said in a statement to the press.
Rodríguez told police he has “no memory” of shooting the two forestry agents and that the last clear memory is of them approaching with a greeting of “good morning,” before they asked him to ”please empty your gun”.
In his statement he reportedly said he had done so “instinctively” but can't remember pointing it at the forestry guards.
The double-murder has provoked calls to revise Spain's gun control laws.
“We need to establish stricter requirements to obtain the license of arms, and a much more careful control of the people who go out to hunt,” said Spanish NGO Ecologistas en Accion in a statement.
Catalonia's Interior Minister stressed that although such “isolated” incidents shouldn't lead to the demonization of the hunting community, the regional Catalan police force, Mossos d'Esquadra, should be given extended authority over the issuing of licences, which is currently under the jurisdiction of the Guardia Civil.
Trubutes were paid to the fallen park rangers with a minute's silence held at the Catalonia's Department of Agriculture.