Lorenzo ISD Superintendent Jerrod Pickering said the incident happened around 2:15 p.m.
"At no time was any student in danger it's done nearly as a precaution," said Pickering.
Pickering said students were not allowed to leave their classrooms, and they were released at the end of the normal school day at 3:30 p.m.
But parents were not happy with how late they were informed about the lockdown. Lorenzo High had a scheduled school board meeting at 6 p.m. Monday afternoon, where several angry parents expressed their frustration.
"Everybody was scared. Everybody wanted to know what was going on. I mean that's are babies in there. If something happens to them we don't get them back," said Marisa Davis a parent at Lorenzo High School.
Virginia Mendoza, also a parent at the school, agreed.
"He [Pickering] did good. It's just the thing is he didn't let us know on time and we were scared," said Mendoza.
Crosby County Sheriff, Ethan Villaneueva, said a gun was involved in the dispute and that no further information has been released on the incident.
"We just know that a domestic came over onto the campus.. It was told that there was a hand gun involved," said Villaneueva. "We made sure the threat was not on the school, which it wasn't."
Villaneueva said neither of the people involved in the dispute have been located.
Stay with EverythingLubbock.com, KAMC and KLBK News for more as this story develops.