Tests of a substance found inside the van driven by a man shot to death by immigration officers last month in Houston revealed it wasn't methamphetamine, U.S. Attorney Aaron Reitz confirmed to The Texas Tribune.

"I can confirm what's already public: lab testing showed the substance in the baggies was not meth," Reitz, the U.S. attorney for the Southern District of Texas, said in a statement to the Tribune.

Reitz didn't say what substance was actually in the plastic bags the FBI found in the van driven by Lorenzo Salgado Araujo, the 52-year-old Mexican shot by Immigration and Customs Enforcement officers on July 7.