Authorities in Arizona are hoping old-fashioned fliers advertising a $50,000 reward helps lead them to whoever has been behind a string of shootings on vehicles on or near a Phoenix-area interstate.
Overhead signs have already been places along Interstate 10 in Phoenix, where at least 11 vehicles have been shot at since Aug. 29. On Monday, a reward for information leading to an arrest was increased to $50,000.
"We're looking for one tip, one specific tip that leads us to the arrest of this person involved in this," Arizona Department of Public Safety spokesman Bart Graves told reporters Tuesday.
The department has received over 1,000 tips and 550 are under investigation, NBC station KPNX in Phoenix reported.
The string of shootings has been called domestic terrorism. A "person of interest" was detained on Friday and questioned about the shootings, but was never named as a suspect and was booked on an unrelated possession of marijuana charge, officials said.
On Sunday, three 18-year-old men were arrested in slingshot attacks on cars and pedestrians that have been characterized as copycat attacks.
One of the three, Aaron Nottingham, told NBC station KPNX that the attacks were not designed to capitalize on fear over the shootings, but that they "were just a few teenagers going out and having fun."
Graves said Tuesday that, "despite what they're saying to the media, they clearly were trying to disturb the peace of mind and the safety of drivers on the road." The three were booked on charges of assault, endangerment and criminal damage, the Maricopa County Sheriff's Office said.
A 13-year-old girl was injured by flying glass in the spate of freeway shootings but there have been no other injuries.
The shootings have different characteristics: Eight involved bullets, and one of those vehicles — on Sept. 6 — was involved in an earlier "road rage" incident, police said. Three of the shootings involved some sort of projectile, authorities said.
The shootings have left some drivers in the Phoenix area on edge. Three people reported broken windows from Monday night and Tuesday afternoon, but all were determined to have been caused by road debris, the department of public safety said. There have been no shootings since Thursday.