The victim identified only as Hee, in his 50s, has been working as a supervisor at the shop for several years.
According to a family member, based on the medical reports, Hee could have been hit several times from behind with a blunt object, resulting in him sustaining fractures to his skull.
It was learnt that a security guard who clocked in for work at about 7pm found the unconscious man in a pool of blood inside the premises with the shop's door ajar.
Family members claimed a certain amount of cash kept in the cash register was also missing.
However, attempts to get further comments from the Penampang police were in vain.