JACKSONVILLE, Fla. -

Authorities say a Tampa man forgot to turn off his car, resulting in the death of his 23-year-old neighbor earlier this month.

Tampa police confirmed on Wednesday that 22-year-old Andrew Grywalski wasn't distracted and or under the influence of drugs or alcohol when he pulled in the garage at his apartment complex on Sept. 1. They've deemed the death of Rebecca Hawk a "tragic accident," and no charges will be filed.

Grywalski told police his 2011 Mazda 3 is a quiet car, so he thought he had turned if off when he drove home from art class that afternoon. He went inside to have dinner with his dad, accidentally leaving the key in the ignition, and the car ran overnight in the garage for 11 hours, police said.

Several hours later, police said, Grywalski noticed a strange smell and thought it was a mold problem or a dead animal in the wall. He reported the problem to maintenance and went to bed, police said.

At 8 a.m., he woke up and noticed the smell was stronger, according to a police report. He started checking the rooms, opened the garage and realized his car was still running. He was smelling exhaust.

Meanwhile, a woman in the building told a supervisor she was feeling lightheaded. The maintenance supervisor evacuated the building.

Officials say Hawk died from carbon monoxide poisoning as she slept. The garage shares a wall with Hawk's bedroom, where the poisonous gas seeped into. Hawk's 20-year-old roommate, Kashaundra Joyner, was hospitalized.

Several others at the apartment complex were taken to a hospital, but Hawk is the only one who didn't survive.

Police spokeswoman Laura McElroy says Grywalski was devastated to learn Hawk had died.

Rebecca Hawk graduated from Forrest High School in Jacksonville in 2006. She was one week into her dream job, a child protective investigator with the Hillsborough County Sheriff's Office in Tampa, her parents said.

"Very adventurous, very bold, accomplished the things she set out to do," Doug Hawk said earlier this month of his daughter.

"When we found out what happened, we couldn't even imagine that could happen because it's never, ever, ever entered our minds, not for one second," Sandra Hawk, Rebecca's mother, said earlier this month. "She just graduated from college, she was just starting her career, she was just beginning her life. ... It's too soon. It's too early for her life to be over."

According to the Centers for Disease Control and Prevention, about 500 people die in the U.S. each year as a result of unintentional carbon monoxide poisoning.

Health officials say carbon monoxide exposure also results in about 15,000 emergency room visits each year. Experts say that many of the symptoms, such as headache and nausea, can be mistakenly blamed on other causes, like an illness.

"In general, people have the warning signs first, so they can get out of the environment, and that's why they're OK," said Dr. Erin Berk, of University of Florida Emergency Medicine. "But the super dangerous times are when people are asleep and they're exposed, so they don't know any of those dangers, and then they progress to the sleepy zone and they're already asleep, so they don't know what's happening, and they go on to have a coma and then they can die."

That's what happened to Rebecca Hawk, doctors said.

Sandra Hawk said she hopes other people learn from this.

"We're glad that we have an opportunity to tell Rebecca's story because Rebecca would say, 'Mom, if somebody else could be saved, if this could help somebody else, then my sacrifice was worth it,' because that's just the kind of person that she was," Sandra Hawk said.

Health officials recommend all residents have a carbon monoxide detector in their homes.