The ophthalmologist was last seen on Monday, March 21, at her office in Highland, Ind.
The disappearance of Dr. Mehta-Paul is being described as unusual by police in both Highland and Munster, Ind., who are conducting the investigation.
On Sunday afternoon, authorities asked for the public's help in locating the physician who's been missing now for almost a week.
When asked if there was any indication of foul play, Munster Police Chief Stephen Scheckel said: "At this point, we're leaving all options open. We just don't know at this point in time."
But after relatives both here and in her native India could not reach her by cell phone, and when she didn't show up for her morning rounds at an area hospital on Tuesday, co-workers and her family notified police.
"It's a very quiet neighborhood -- haven't noticed any problems at all. It's sort of surprising. I have no idea what could have happened to her," said Mehta-Paul's neighbor Dr. Stuart Klein.
Mehta-Paul is about 5-feet-1-inch tall and weighs about 130 pounds. She has brown eyes and brown hair.
Highland police are also assisting with the investigation because of a bank video that shows Mehta-Paul making a night deposit.
She was driving her gold 2001 Toyota RAV4, and it's missing, too.
"There are two First Financial locations in the town of Highland. I'm not sure at which location the deposit would have been made," said Highland Police Commander George Georgeff.
The 70-year-old Mehta-Paul is divorced and lived alone in her Munster home until recently.
That's when one of her three sons relocated from California and was staying at the address.
While police have spoken to the son, his exact whereabouts are unknown.
Investigators did check the eye doctor's residence shortly after her disappearance, only finding the son's 1997 Acura still in the driveway but missing a California license plate.
The doctor's SUV could have its Indiana license plate DW2031, or the California license plate 6LHZS319.
Since she has been missing, there has been no activity on either her cell phone or credit cards.
Family, friends and co-workers remain concerned.
"It is completely out of character. That's why we're keeping all options open at this time," Scheckel said.
Anyone with information about the whereabouts of Dr. Promila Mehta-Paul is asked to call either the Munster Police Department at 219-836-6600 or the Highland Police Department at 219-838-3831.