PHOENIX - The Department of Public Safety is investigating four incidents involving shots being fired at vehicles on a Valley freeway over the last several days. 
 
 The first two incidents happened along Interstate 10 on Saturday morning between 11 and 11:10 a.m. at 19th Avenue and 59th Avenue. The third shooting happened around 10:15 p.m. on I-10 at 16th Street. 
 
 DPS spokesman Frank Milstead said that a fourth shooting had been reported at 4:25 a.m. Monday on I-10, also near 19th Avenue. 
 
 During a Monday press conference, Milstead said it appears the shooting incidents are random and there is nothing about the targets that appears to be related. He also warned Valley drivers to stay vigilant as these continued incidents "could end in tragedy" if the suspect is not located. 
 
 "I couldn't tell you what their intent is. I just know we've had bullets hit the sides of the cars, we've had bullets hit windshields so they've hit on different parts of the cars," explained Milstead. 
 
 A 13-year-old girl suffered a cut to her right ear Saturday morning when a bullet pierced the windshield of the SUV in which she was riding, the DPS said in a press release. She was treated at the scene and didn't need hospitalization. 
 
 The other bullets hit the sides of the vehicles and a headlight. 
 
 Milstead said some of the motorists didn't immediately realize their cars had been shot, thinking the loud noise they heard was an object on the highway that struck their vehicle. 
 
 "A man driving a work truck heard a loud bang and thought that a rock struck the company truck," the press release said of the Monday shooting. "When he and other passengers arrived at their work site, an inspection of the company truck revealed the driver side front headlamp" had been hit by a bullet. 
 
 Milstead said detectives are working non-stop to identify the shooter, and are asking for the public's help to report any suspicious behavior. 
 
 Anyone with information is asked to call Silent Witness at 480-WITNESS or contact DPS at 602-223-2212. ||||| PHOENIX (AP) — Authorities are trying to determine if the same person fired gunshots at four vehicles along a Phoenix freeway over a three-day span. 
 
 This Saturday, Aug. 29, 2015 photo provided by The Arizona Department of Public Safety shows a SUV window shattered by a gun shot in Phoenix. Authorities say shots were fired at several vehicles on Interstate... (Associated Press) 
 
 Only one person was hurt in the shootings that began Saturday along Interstate 10, and that unidentified person suffered a non-life-threatening injury, according to authorities. 
 
 "You should be concerned. We have some people or person shooting at moving vehicles on I-10," Arizona Department of Public Safety Director Frank Milstead said at a news conference. "It has not ended in tragedy, but it could." 
 
 Authorities are asking for information from anybody who saw anything unusual on the freeway around the times when the shots were fired. 
 
 "Somebody knows something," Milstead said Monday. "We're not sure if these shootings are random or related. We don't know what the intent is. It's not known at this point if it's a copycat crime." 
 
 Two vehicles were struck within a half hour around 11 a.m. Saturday on I-10 between 19th and 59th avenues, and a third vehicle was hit on I-10 near 16th Street about 10:15 p.m. Saturday, according to the DPS. 
 
 A fourth vehicle was shot at around 4:25 a.m. Monday near 14th Avenue and I-10. 
 
 All of the shootings occurred within an 8-mile stretch of the freeway, which runs through central Phoenix. 
 
 A tour bus and an SUV were two of the vehicles fired upon, but DPS is withholding other specifics so the investigation won't be jeopardized. 
 
 The bullets have hit a windshield and a headlight, and the rest have been impacts on the passenger sides of the vehicles, Milstead said. ||||| On August 29, 2015, between 11:00 a.m. and 11:30 a.m., Arizona State troopers investigated two separate shooting incidents along Interstate 10. 
 
 The first shooting occurred eastbound along I-10, at approximately 11:03 a.m. A sport utility vehicle was fired upon and struck. The front seat passenger, a 13 year old female, sustained a cut to her right ear, and was treated on-scene by the Fire Department; she was not transported. 
 
 
 
 The second shooting occurred westbound between 35th Avenue and 59th Avenue, at approximately 11:09 a.m. A passenger-type bus was fired upon and struck. Only the driver was on-board and he was not injured. 
 
 
 
 The third shooting occurred eastbound near 16th Street, at approximately 10:15 p.m. The victim stated she heard a loud banging sound however, she did not inspect her vehicle until Sunday 8/30/15; that is when she noticed bullet holes on the passenger side of the vehicle. 
 
 
 
 On August 31, 2015, a fourth shooting occurred eastbound near 24th Street, at approximately 4:25 a.m. A man driving a work truck heard a loud bang and thought that a rock struck the company truck. When he and other passengers arrived at their worksite, an inspection of the company truck revealed the driver side front headlamp had damage consistent with a bullet strike. 
 
 
 
 These incidents are under investigation by detectives. Anyone with information is encouraged to contact the Arizona Department of Public Safety and submit a report here: https://www.tipsubmit.com/webtipforms/webform.aspx?id=25&AgencyID;=807 
 
 Photos 
 
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 The Arizona Department of Public Safety is a state-level law enforcement agency whose mission is to protect human life and property by enforcing state laws, deterring criminal activity and providing vital support to the State of Arizona and its citizens. 
 
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– "You should be concerned," a spokesperson for the Arizona Department of Public Safety said during a press conference yesterday. "It has not ended in tragedy, but it could." The AP reports four vehicles have been struck by bullets while traveling along an 8-mile stretch of Interstate 10 in Phoenix, with a 13-year-old girl being the sole injury so far. According to ABC 15, the shootings took place between Saturday morning and yesterday morning, and no suspects or motives have been identified. "We've had bullets hit the sides of the cars; we've had bullets hit windshields," says the DPS spokesperson. Since Saturday, bullets have struck an SUV's window, the headlight of a work truck, and the passenger sides of a tour bus and another vehicle, DPS states in a press release. ABC reports that a 13-year-old girl was cut on the ear when a bullet pierced the SUV, with photos showing a bullet hole in the passenger-side window. At the moment, the shootings appear to be random, and drivers are being warned to stay vigilant. The AP reports police are looking for witnesses and trying to figure out if the same person is responsible for all four shootings.