Image copyright CBS Image caption The dead infant was found at one of Amazon's several locations in Phoenix

Police are investigating the death of a baby girl who was found in the restroom of an Amazon warehouse in the US state of Arizona.

Phoenix police spokesman Vincent Lewis said the newborn was reported to police at the online retail giant's facility on Wednesday evening.

Homicide detectives are working to determine if any crime was committed at the facility, he said.

Police have identified the mother, who is co-operating with the investigation.

In a press conference on Thursday, Sgt Lewis refused to publicly name her or say whether she is employed at the distribution centre.

"But, again, the restroom was located inside of a secured Amazon facility," said Sgt Lewis, who refused to speculate on what charges the mother may face.

He said that investigators are looking into whether the child was born in the toilet, adding that the infant appeared to have only been there briefly.

"It had been there some time," he said, adding, "very recent, same day".

"It appeared to first responders that the baby was full term, or close to that," the spokesman said, adding that she could not be resuscitated by medics from the city's fire department.

According to local media, the child was discovered in a rubbish bin by a maintenance worker.

Amazon said in a statement: "This is a terribly sad and tragic incident.

"We are working with local authorities to support their investigation.

"The safety and wellness of our team is our top priority."