Police responded to calls about multiple shots fired in the parking lot just after 3:30 Monday afternoon.
Authorities tell Action News one man was killed, but several others may have been injured. They have not yet released the identity of the victim.
KEPR also talked to the Gotta Stop store manager, who says she first heard gunfire while she was in a back office. She says she looked outside to see a man being chased through the parking lot by a group of several other men.
She and a co-worker ran back inside. But she tells Action News, she later watched surveillance video that showed the entire group exchanging gunfire, until the victim tried to get into an SUV and was killed.
Umatilla Co. District Attorney Dan Primus confirms, "There are some security tapes that we have had an opportunity to look at. And right now we are simply trying to ascertain as much information about this incident as we can."
State, County, and local authorities are now joining the investigation, from the Morrow/Umatilla Major Crime Team.
Hermiston Police say they cannot deny the shooting was gang related, but are not yet able to confirm it either.
They openly admit the investigation will now be a considerable strain on all available resources.
So far, no arrests have been made. Authorities tell Action News they have questioned several witnesses and persons of interest.
This is a developing story. Check back on KEPRTV.com often for the latest details.