Khun Jintana, 42, had been Human Resources Manager at the Hilton Phuket Arcadia Resort and Spa on Karon beach for about six months.
Previously she had worked at two ther Phuket five-stars, the Dusit Thani Laguna Phuket and the Anantara Phuket Villas.
Police have now discounted any links with those resorts to her death and are now concentrating on possible disputes at the Hilton, Phuket's largest resort.
Khun Jintana was gunned down on Friday at a t-junction in Phuket City when a motorcycle pulled alongside her white Chevrolet and a single shot - probably from a handmade thai pradit pistol - was fired through the driver's window.
It's understood Khun Jintana was regarded as a highly efficient HR manager whose suggestions for changes were frequently taken up.