A federal investigation is now underway into an email hoax that prompted some school districts to dismiss classes early, including Lasara Independent School District.

Lasara is a tiny school district in Willacy County. It serves a community with a population of fewer than a thousand people. So when a school day is suddenly cut short, news travels fast.

"In my days and my times, we wouldn't go through these things," parent Maria Hayes said.

Someone emailed a bomb threat to Lasara on Monday, which prompted district officials to dismiss classes early. School districts across the Valley reported receiving emailed bomb threats.

"Threats were made throughout Texas and outside of Texas," Mission Police Chief Cesar Torres said. "There is nothing to substantiate that there was a credible threat."

Local, state and federal investigators are now working to figure out who did it, and why.

"We're hoping it's not a student who's doing this," Torres said. "In Texas, anyone who's 10 years of age or older can be prosecuted."

Whoever is responsible not only disrupted classes in Lasara, they also caused "worry" among parents everywhere.

"There's a genuine concern for what is happening," Willacy County Sheriff Jose Salazar said.

Classes in Lasara are scheduled to resume Tuesday.

Investigators believe this was a hoax that probably originated outside the Valley.