MEXICO CITY – Mexican prosecutors said their investigation into the shooting deaths of 22 suspected criminals at a warehouse last month has found that none of the people were shot at close range.
Questions arose about the June 30 shootout with military forces in which all of the suspects were killed, but no soldiers died, even though the suspects allegedly opened fire first.
The prosecutors' office of Mexico State said in a statement sent to The Associated Press late Thursday that it has "no evidence at all of possible executions." The office said it found ballistic evidence of "crossfire with a proportionate interchange of gunshots."
But reporters who visited the warehouse did not see signs of an extended gun battle. About five spots along the warehouse's inside walls showed the same pattern: one or two closely placed bullet pocks, surrounded by a mass of spattered blood, giving the appearance that some of those killed were standing against the wall and were hit by one or two precise shots at about chest level. There were few signs of any stray bullets or near misses of the kind that would be expected in a large gun battle.
The prosecutors' statement did not release any of the autopsy or ballistics reports. Nor have federal or state prosecutors responded to repeated requests for that information.
The statement said a chemical test for gunshot residue indicated the dead suspects had fired weapons, but did not specify how recently.
But experts called into question Mexico's reliance on a relatively primitive and partial chemical test for gunshot residue. Modern police departments use a clean swab and an electron scanning microscope to identify three 'signature' elements of gunfire — barium, lead, antimony. Mexico's chemical-reaction method tests only for lead, and is usually used by police in other countries to test suspected bullet holes on clothing, not a suspect's hands.
"It doesn't sound right," Ronald R. Scott, an expert ballistics witness and former commander of the Massachusetts state police firearms section. "That's not the gold standard."
Moreover, Scott said, gunfire in an enclosed space like the warehouse probably would have left some residue on the suspects' bodies even if they hadn't had fired a gun, because the residue spreads in the air. Soldiers who had gunshot residue on their hands and uniforms also apparently entered the warehouse, spreading it further.
Soldiers or police may have even further contaminated the crime scene: the floor of the warehouse was scattered with broken parts of cellphones, because someone — apparently soldiers or police — broke the phones to extract the SIM cards, which contain information about the owner and his calls. Extracting the phones from the dead suspects' pockets and handling the bodies could easily have contaminated them.
"It seems to there's a significant question of reliability and validity," Scott said of the test results.
The state prosecutors said they have turned the investigation over to federal authorities.
Mexico's Defense Department says soldiers were patrolling in a violent corner of the country on June 30 when they came under fire from a warehouse where a gang of 21 men and one woman were hiding. One soldier was wounded, but all of the suspects were killed.
The shootout was the most dramatic in a string of battles in which the army says criminals fired first at soldiers who then killed them all, while suffering few or no losses. There have been so many such incidents that human rights groups and analysts have begun to doubt the military's descriptions of the events.