PHOENIX — A woman who found her 17-month-old son dead in her hot, stuffy car after she worked her seven-hour shift as a Hooters waitress has been arrested, police said Wednesday.

Ashly Duchene, 22, was booked into Maricopa County jail on a felony count of negligent homicide, police said.

Duchene usually dropped the boy off at a day-care center on her way to work, but for unknown reasons failed to do so Tuesday, police Sgt. Joel Tranter.

Instead, she left her son, Ryan Gallagher, in the car when she arrived at the north Phoenix restaurant at about 10 a.m., police said. When she returned after her shift at nearly 5 p.m., he was dead.

Efforts to revive the boy by witnesses, officers and firefighters were unsuccessful. Temperatures hit nearly 90 degrees Tuesday, but it would have been more than 100 degrees inside the car, Tranter said.

Duchene told police she walked to her car, unlocked the driver’s door, sat in the vehicle and immediately realized she had forgotten she had left Ryan in the back seat.

Officials believe the boy, who was in a car seat, was invisible to people going in and out of the restaurant and a nearby car wash because the car has tinted windows.

A request to interview Duchene was not immediately answered by police Wednesday morning.

The restaurant was closed Wednesday and was holding counseling sessions for employees.

“Our company is deeply saddened by this terrible tragedy,” said Melanie Gulmetti, a regional marketing manager. “Our thoughts are with the mother and her family. We are cooperating fully with authorities.”