The woman anonymously called the authorities at 12.35am on June 16, claiming she had just given birth before hanging up, prompting serious concerns for her and the baby’s safety.
The call was made from a public pay phone at the corner of Shelley Street and North East Road at Tea Tree Gully, Adelaide.
Investigators say the woman sounded distressed and they believe she is in urgent need of medical assistance.
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Police and SES officers have searched the area but have not been able to locate the woman or her child.
The woman has been asked to contact the authorities again as concerns for her safety mount.
Anyone with information, dashcam footage or CCTV footage from the area is urged to contact the police.