Update 3:45 pm
Grandview police have detained a suspect in connection with the incident, according to the Yakima County Sheriff's Office, and the school lockdown has been lifted.
Update 1:09 pm
Deputies from the Yakima County Sheriff's Office and officers from the Sunnyside and Mabton Police Departments have arrived on scene and are investigating.
Deputies from the Yakima County Sheriff’s Office and officers from the Sunnyside Police Department are en route to Mabton to respond to a threatening situation that has prompted a school lockdown there.
Shortly before noon someone at the Blue Sky Market, 340 North Street, called to report a male had grabbed some 9mm bullets, said he was going to kill someone on 7th Avenue, and then left in grey Mercedes sedan, according to Casey Schilperoort of the sheriff’s office.
The Blue Sky Market is across the street from the Mabton School District offices and about a block from the district’s junior and senior high school, which is what prompted the lockdown.
The Mabton school district is on lockdown because of a situation in that community, the district said in a Facebook post.
This story will be updated