Police say two truck drivers have been added to the growing list of victims that have been targeted by the Interstate 10 gunman over the last few days.

In total, 14 vehicles were shot at or hit by projectiles in the last 11 days near Interstate 10 in Phoenix. Today marks the first time that a commercial truck driver was targeted.

The first truck driver noticed a bullet hole in the side of his rig during his pre-trip inspection after taking control of the truck from another driver. He was not inside his rig at the time of the shooting.

The second driver called police after noticing bullet holes in his rig when he stopped at a truck stop near Interstate 10.

According to the Washington Post, Col. Frank Milstead of the Arizona Department of Public Safety called the attacks “domestic terrorism”. The Arizona DPS also tripled the reward to $20,000 for information leading to the shooter’s arrest.

No one has been injured in the highway shootings, but the DPS believes it’s only a matter of time before somebody gets hurt or killed.

The Department of Safety’s spokesman, Bart Graves, said that he would not change plans or postpone travel to the area because of the shootings, but advised travelers to “be aware” of their surroundings.

Anyone with information related to the shootings is asked to call the silent witness hotline at (480) 948-6377 or the DPS at (602) 644-5805.