Dallas Fire-Rescue and the Dallas Police Department responded to the ICE facility on North Stemmons Freeway in Dallas Friday morning on a report of a suspicious package. DFR confirmed that the hazmat team was investigating an unknown substance, but preliminary testing found that it was not dangerous. 

A law enforcement source tells CBS News Texas the substance was corn starch.

In a statement issued Friday afternoon, an ICE spokesperson said an ICE officer opened an envelope addressed to "Dallas Field Office" and found the white powdery substance inside. A shelter-in-place order was issued until the powder was found to not be hazardous, and the facility resumed normal operations.

A second envelope was sent to an ICE office in Irving, the statement said.

The Dallas facility is the same one that was targeted by a shooter in September. A shooter who was targeting ICE agents killed two detainees and another hospitalized was hospitalized. The suspect, identified as Joshua Jahn, died from a self-inflicted gunshot.  

A DFR spokesperson said that the FBI would be taking over the investigation.