Bellaire High School was put on lockdown Tuesday morning after receiving an unspecified threat, according to Houston Independent School District (HISD) police.
As part of the school's security plan, it was placed in "secure mode" while planned activities continue -- all students were said to be safe.
In an email sent Tuesday morning to parents, Bellaire went into a "secure hold" plan by order of school officials while HISD police investigated the threat.
It was the latest in a series of threats against Bellaire -- and other HISD schools -- this school year, which ends in five weeks.
Students at the school on Maple St. in Bellaire continued taking STAAR end of course Algebra tests as planned, even as the threat investigation continued.
The school was among the first HISD campuses to install a weapons detection system, according to the Houston Chronicle.