Authorities now believe a rock is responsible for taking down a Customs and Border Protection (CBP) helicopter in Roma.
The helicopter made an emergency landing in a vacant lot on Tuesday afternoon.
CBP Air and Marine officials released preliminary investigations results about the emergency landing on Thursday evening.
Investigators said a person, who has not been identified, threw a rock that struck the helicopter TMs rotor blade.
The damage forced the helicopter to make an emergency landing.
According to initial reports, that person who threw the rock was on the Mexican side of the Rio Grande River but investigators said they have not been able to determine exactly where the rock attack originated.
CBP Air and Marine officials said a two-person crew aboard the American Eurocopter AS350 Single Engine helicopter was not harmed.
Damages estimates were not immediately available but CBP Air and Marine officials condemned the attacks.
Assaults, like this one, are dangerous, unnecessarily put the public's safety and officers lives at risk, and typically cause thousands of taxpayer dollars in damages, the agency said in a prepared statement.