Detective Chief Inspector Mark Power said it was too early to say whether the circumstances surrounding the death were suspicious.
He added: "We would like to hear from anyone who was in and around the area of the Sainsbury's car park between the hours of 1.30am and 3am. The car park is quite active late at night, as people drive through to use the cashpoint or walk through as a short cut.
"In particular, we would like to hear from you if you were driving through the car park or if you were the young couple who were spotted walking through the car park holding hands. You may hold information that would assist us in our inquiries, so I would urge you to speak to us."
Anyone with information is asked to contact police.