The Avondale Police Department said La Joya High School is on lockdown as officers conduct an investigation at the school.
Police said they were investigating a threat, but said the school was on lockdown as a "precaution."
Later police tweeted that school would be released early Monday.
Police said the investigation led to the arrest of one of the school's students. The student told police the threat was made in order to cancel school.
Police said there was no evidence that the threat was going to be carried out.
There are no further suspects, and the school will resume as normal on Tuesday, police said.
