A social app posting of a vague threat led to a police presence at Oakdale High School on Friday, Oct. 17.

Oakdale Police Chief Lester Jenkins said police were made aware of an anonymous threat to cause a school shooting for Friday morning on a social media site around 11:30 p.m. on Oct. 16. Police were initially unable to verify the threat or get additional information to substantiate the threat but assigned units to be at the school throughout the day.

“As we would with any of these incidents, we’re investigating to see if there’s anything to it,” Jenkins said.

Parents received an “all-call” message from the high school around 9:30 a.m. advising  that “…a threat made by an unknown person on an obscure blog was being made at Oakdale High.”

The advisement informed parents about the police presence and encouraged teachers and students to come forward with any information.

According to those who were involved with the investigation, the blog or app the threat was made on is known as Yik Yak, which allows users to post 200-character status updates anonymously.

Those updates can be seen and voted on by other Yik Yak users within a mile and a half of them. The posts are text only.

Oakdale Joint Unified School District Assistant Superintendent Larry Mendonca said the district was notified of the threat by the police department and cooperated with their investigation.

Mendonca said the district called in Interquest canine services that they are contracted with to assist in any weapon or drug detection at the school.

“There was enough of a threat to create a concern,” said Mendonca, who spent the day at the high school. “At this point, there doesn’t appear to be any legitimacy or credibility to the threat.”

Jenkins said the investigation is continuing and investigators are working with the site to identify the person who posted the threat by obtaining any needed search warrant or court orders.

Yik Yak was founded in October, 2013 by two recent college graduates from South Carolina and is aimed at college students, but a majority of high schoolers have found it popular.

To avoid school interruptions, Yik Yak has blocked access to the app from most elementary and high schools in the U.S. by identifying a phone's GPS coordinates, and it has cooperated with police to identify anonymous users who post threats. The app is marketed for ages 17 and older, though Apple and Android app store accounts are available to anyone 13 and older, however users are not required to input their age when they download the app.

A sampling of posts in the afternoon of Oct 17 revealed a number of posts about the threat of a shooting but also showed an assortment of comments mostly about sex, high school gossip and drugs.

Anyone with information regarding this incident should call the Oakdale Police Department at (209) 847-2231.