Several gratuitous posts on a Summerville High School student’s social media account featuring a threat of violence to an unidentified school and sexual and racist content prompted an investigation by the Tuolumne County Sheriff’s Office and the school’s administration on Thursday.

Following a day-long investigation that concluded about 3 p.m., investigating deputies and school administration determined that the student’s Instagram account, a smartphone social media app used to share photographs and corresponding captions, had been hacked by another Summerville High School student as a “practical joke.”

“We are still dealing with the fallout of what to do next, but the details of it have been completed, and the main thing is there was no credible threat. There was no specific threat, there were no weapons, there was no plan,” said Summerville Union High School District Superintendent Robert Griffith. “There was a teenager who thought they were doing some kind of practical joke that turned out wasn't too funny.”

Griffith said he had not been able to view the Instagram posts during the course of the investigation, but Summerville High School Principal Diana Harford had seen them.

Tuolumne County Sheriff’s Office Public Information Officer Sgt. Andrea Benson said investigating deputies had also seen the images, but would not release specific information on the posts due to the nature of the topics.

Benson also confirmed that the images had been posted publicly to Instagram and featured captions with threatening, sexual or racial content.

The social media posts were made overnight Wednesday and were reported to school administration by both students and parents Thursday morning, Griffith said.

Administration “hopped right on” to investigating the posts on the student’s account, Griffith said, and determined there was no legitimate threat targeting Summerville High School.

“There were things taking place that he didn't have control over,” Griffith said. “Our concern was, even though it didn't have a school listed, it didn't have a specific threat, it did not have a timeline, there wasn’t really anything other than they wanted to do some harm, it was popping up in our kids’ social networks.”

A news release from the Tuolumne County Sheriff’s Office noted that the student responsible for the “prank” had been identified from investigative deputies on the school campus.

A report of the incident has been referred to the Tuolumne County Probation Department for review because the incident involved a juvenile, Benson said.

She indicated that this decision was standard procedure for situations involving juveniles, and the possibility of charges would be based on the Probation Department’s review of the report.

Griffith said that Summerville High School administration was still determining the appropriate action, but that there would “likely be some discipline” for the responsible party.

The social media threat at Summerville High School is the third social media incident to arise in Tuolumne and Calaveras counties in the past few weeks.

On May 16, unsubstantiated social media rumours associating a runaway teen with the burglary of guns in the Crystal Falls area of Sonora prompted the closure of Curtis Creek Elementary School and Gold Rush Charter School and put Foothill Leadership Academy on lockdown.

During the incident, a photograph of two hands on Snapchat and a false insinuation by a student quickly unraveled into a panic as parents, students and school administrators speculated on the credibility of a threat to Curtis Creek Elementary School.

The Tuolumne County Sheriff’s Office determined that day that the threat was not legitimate, and the student had done nothing wrong.

On May 31, two Mark Twain Elementary School students threatened to “shoot up” Mark Twain Elementary School, Calaveras River Academy and Calaveras High School over the messaging component of Facebook.

Investigating Angels Camp Police Department officers determined the students were not a credible threat and did not have access to weapons. They made the comments because they were upset about poor grades in the final days of the school year, a news release stated.

The students will not attend Mark Twain Elementary School for the remainder of the year and may face disciplinary action from the school’s administration, Mark Twain Union Elementary School District Superintendent Julia Tidball said.

Griffith emphasized that area students should enhance their awareness of social media’s permanence and understand an adult’s responsibility to investigate suspicious posts.

“Those in charge of safety, we take it 100 percent seriously,” he said. “It is called the World Wide Web for a reason. People find out.”

Contact Giuseppe Ricapito at (209) 588-4526 or . Follow him on Twitter @gsepinsonora.