The FBI is investigating the theft of medical records of patients at Grady Memorial Hospital, officials said Friday.

Grady spokeswoman Denise Simpson provided few details on the thefts that were discovered late Thursday. She said it remains unknown how many patient records were stolen, which patients were affected or how the records were stolen.

The records pertained to recorded physician comments that Grady sent to a vendor to transcribe into medical notes. The records were stolen from a subcontractor employed by the vendor. The missing records were kept on computer files.

Grady officials do not at this point believe the records contained patients' Social Security numbers or financial information such as credit card numbers, but Simpson emphasized that investigators are only starting their inquiry.

Simpson did not identify either the vendor or subcontractor.

"We sincerely regret the occurrence of this breach of confidentiality of patient records in the hands of one of our vendors," Simpson said in a prepared statement, "and we are hopeful that our quick response to this theft will significantly reduce any negative consequences for our patients and the physicians who care for them."

She said Grady would notify the patients as soon as possible.

It is unclear who might have stolen the records or for what purpose, she said.