The investigation into the June 13 killings of nine police officers in the western province of Quetzaltenango has led to the arrest of 34 suspects, Guatemala's interior minister said Wednesday.

Police, soldiers and personnel from the Attorney General's Office carried out 128 separate searches in just the last two weeks as authorities pursue the chief suspect, Mauricio Lopez Bonilla said.

Investigators say the killings were ordered by Eduardo Villatoro Cano, reputed leader of the Guatemalan branch of Mexico's Gulf drug cartel.

On the night of June 13, attackers wearing ski-masks arrived at the police barracks in Salcaja, Quetzaltenango, entered the building and shot the officers - some of whom were in bed - at close range.

Dubbed "Operation Dignity," the probe of the massacre began with intelligence work to identify the hideouts of Villatoro's group, Lopez Bonilla said on the radio program "Face-to-face with the President."

The teams carrying out the arrests have confiscated 33 handguns and 12 rifles, large amounts of cash in dollars, Guatemalan quetzales and Mexican pesos, as well as 65 vehicles, 43 thoroughbred horses and 67 fighting roosters, the interior minister said.

Homes and ranches have also been seized, he said.

Operation Dignity has likewise uncovered a cache of drug precursor chemicals and what appears to be a laboratory for the production of synthetic drugs, Lopez Bonilla said.

So far, he stressed, not a single shot has been fired in the course of Operation Dignity.

Besides the police deaths, Villatoro Cano's outfit is thought to be responsible for more than 100 homicides in Huehuetenango province, bordering México. EFE