(TULSA, Okla.) -- Slain Oklahoma teen graduate Kayla Ferrante said to her boyfriend Neikko Perez, "Call 911. I can't breathe," after a mystery suspect fired a bullet through the license plate of the car that pierced her back and ultimately killed her.
Perez told Good Morning America that he thought the gunshots were "really loud fireworks" and he has "no idea" why anyone would have shot at them.
Kayla Ferrante, 17, graduated from her Tulsa, Okla., high school last Friday, a year early in order to jump-start a career working with special-needs students. Her family said this was her passion.
After a family celebration Saturday, she went to a friend's house and later that night headed for home with her boyfriend Neikko Perez driving the car.
When the couple were just a half block from Ferrante's house, shots rang out that Perez thought were "really loud fireworks." The bullet that hit Kayla pierced the license plate on the back of the car, tore through the trunk and hit her in the back before passing through her. Police later determined the bullets were fired from a high-powered rifle.
About five minutes later, police and medical personnel arrived.
"They told me to get back and they didn't want me near," Perez said. "They started questioning me right after."
Ferrante was rushed to the hospital where she died during surgery, police said.
By the time Perez got to the hospital, he said, "It was too late. It was the hardest thing I've ever had to do, to hear that my girlfriend had passed."
Perez's car had been blocked in the driveway when he and Ferrante had left their friend's house, so he had been driving his brother's best friend's car.
Perez said he has "no idea" why the car was shot at or who could have shot at them. Police are wondering the same thing. And with no witnesses or suspects, authorities are asking for the public's help and searching for a motive in the killing.
"There are a variety of potential motives, but nothing solid at this point," Det. Victor Regalado of the Tulsa Police Department told ABC News. "We're exploring the fact that this could be a random shooting, that it was intentional, that either one of them could have been a target, or both."
Regalado said authorities are still investigating Kayla and her boyfriend's backgrounds, but preliminary investigations show, "Neither one of them appears to have been involved in any type of high-risk behavior, like drugs or gangs."
When asked whether there were any security cameras in the neighborhood that might have captured the shooting, Regalado said, "No comment."
"Based on the penetration, as well as some other things that we've collected, we were able to determine that it was a high-powered weapon," Regalado said. He declined to disclose the model of the weapon.
He said authorities are asking for help from any potential witnesses or even people whose spouses or significant others might have arrived home late Saturday night and acted strangely.
"At this stage in the investigation, we're open to anything," he said. "There's somebody out there that saw something."
"As her family and friends, we cannot understand who would do this or why and desperately want anyone with information to do the right thing and come forward," her family said in a statement. "Kayla was doing nothing wrong. She wasn't in a place she shouldn't have been, she was just a girl coming home before curfew."
Perez teared up when describing his memories of his girlfriend.
"She was shy but not around me. She was one of the nicest people you'll meet. She cared about others, always trying to help others," he said. "She just loved those kids with special needs and I thought that was really sweet of her. She'd always make you laugh, smile. If you're upset, she'd make you smile real fast. She's just an amazing person."
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