TEGUCIGALPA (Reuters) - An anti-graft body backed by the Organization of American States (OAS) on Wednesday accused the Honduran congress of blocking its investigations into a corruption racket that allegedly involves lawmakers and high-level officials.

The OAS Mission to Support the Fight Against Corruption and Impunity in Honduras (MACCIH), unveiled by the Central American nation’s President Juan Orlando Hernandez in 2015, said that a recently passed law will prevent the prosecutor’s office from investigating and charging dozens of possible suspects involved in a graft scheme.

“We don’t understand how it’s possible a law has been passed that seeks to maintain impunity and handicap the battle against corruption,” MACCIH’s Peruvian spokesman, Juan Jimenez, said at a news conference on Wednesday morning.

He added that the new legislation will affect “current and future” probes.

That argument gained steam in the afternoon, when a judge applied the law to acquit five Honduran lawmakers who had been accused of diverting public funds intended for social programs.

“In the morning we brought this up, and it’s happened just like we said,” Jimenez wrote in a Twitter post after the five were released from custody.

The case will now move to a fiscal tribunal.

Heide Fulton, the U.S. chargé d’affaires in Honduras, also decried the measure.

“This action is a monumental step backward in the fight against corruption. Congress must act now to right this dangerous wrong,” she wrote in a Twitter post.

Honduras has been roiled by deadly protests following a disputed Nov. 26 election, which the center-left opposition has accused Hernandez of stealing. The OAS comments reveal the many hurdles to overcome for the poor, graft-riddled country with one of the world’s highest murder rates.

MACCIH has been involved in helping the Honduran prosecutor’s office investigate a 2011-2015 embezzlement scheme that diverted 1.3 billion lempiras ($55 million) destined for social funds, allegedly with the help of more than 60 lawmakers and high-ranking officials.

Jimenez said allies of the president in Congress are among the suspects, adding that the new law would paralyze investigations for three years while the government’s financial authorities trace the diverted funds.

In response, the Congress said in a statement that Jimenez’s comments were “malicious,” adding that the law sought to encourage transparency.

The president’s office did not immediately respond to MACCIH’s comments.