SAN FRANCISCO (KGO) -- The suspect in a deadly shooting at a San Francisco UPS facility may have triggered metal detectors when he entered the building on the morning of the incident.
RELATED: Families continue to mourn as new details emerge on SF UPS shooter
A source with knowledge of the investigation told ABC7's Vic Lee that UPS had a policy called "soft entry hard exit" where security guards check workers who trigger the metal detector at the entrance when they leave to make sure they're not stealing. They are not checked when entering, and that is what happened, according to the source.
RELATED: All 3 San Francisco UPS shooting victims identified
The alleged shooter's backpack set off the metal detectors, but a security guard waved him through, the source said.
UPS issued a statement in response to the development:
"UPS is continuing to conduct its investigation into the June 14 shooting. We do not intend to speculate on the tragic incident, nor comment on the status of our investigation."
Stay with ABC7 News for the latest details on this developing story.
Source: San Francisco UPS driver set off metal detectors on day of shooting