Alien Raiders (2008) on Netflix

Plot summary

Six masked intruders walk into Hastings Supermarket in Buck Lake, Arizona, as the store is closing for the night. They take the staff and remaining shoppers hostage, and one employee is shot. A man named Ritter leads the group. One of his people, Spooky, moves among the captives and says one of them is not human; she is shot when she runs. A police officer in the store kills one of the intruders, calls for backup and shoots Spooky before he is killed himself. Outside, officers gather, and Ritter insists the job be finished. The intruders are scientists who have tracked an alien parasite to the store and intend to find everyone carrying it.