The victim, Parmajit "Paul" Kaila, owned the mini-mart for nearly a year.
Investigators say he was shot to death early Wednesday morning by a relative who also worked at the store. Maninder "Manny" Kaila is being held on murder charges.
Friends and customers say the suspect had been acting different lately.
Investigators have not released a motive. They're continuing to investigate witnesses and family members.
The suspect worked at the store for many years, even under previous owners. Some regular customers say the victim and suspect seemed to have a tense relationship and were often short with each other.