Oldham said that though the threat is believed to be a hoax, the district is taking steps to ensure security for students and staff at Cedar Valley.
"In an abundance of caution, we will have increased police presence and security measures at school today," Oldham said in the email.
The threat originated on Snapchat, Oldham said. He credited student and parent reporting and Round Rock ISD's social media monitoring tools with the discovery of the threat.
On Sunday night, a similar threat was directed toward Hernandez Middle School, district spokesperson Jenny Lacoste-Caputo confirmed to Community Impact Newspaper. Principal of Hernandez Middle School Patricia Ephlin issued an email to parents and staff May 6.
This story has been updated to include information about Hernandez Middle School.