SPRING, Texas -

Newtown, Virginia Tech and now Spring High School.

When students die on campus, the first question asked is, "How do we stop this?"

Like many parents in the Spring School District, Tammi Humphrey, a former teacher in this district and a mother of two children, now running for school board, wants metal detectors installed at all four of Spring ISD's high schools.

Friday, along with community activist Quannel X,  Tammi will lead parents and students in the Spring ISD, to protest at school headquarters, to force the superintendent to install metal detectors at Spring High School before the children return to school on Monday.

"They passed a bond to put metal detectors in the schools and still they have not done it yet," Tammi said.

Tammi is referring to the passing of a bond two years ago, in 2011, in which voters in this district voted to fund the purchase of metal detectors in the Spring ISD.

The bond passed, but the machines were never purchased, and never installed in schools.

Local 2 Investigates did some digging and we found Spring ISD does not require any of its students to walk through metal detectors at any of the district's elementary, middle or high schools.

Likewise, HISD does not require any of it's students to walk through metal detectors.

At Conroe ISD metal detectors are only used at the district's alternative, disciplinary schools, and at football games.

Aldine ISD is the only exception.  At Aldine ISD walk through metal detectors are used regularly at every elementary, middle and high school in the district, because school administrators believe they are a strong way to keep weapons out of the classroom.

Aldine has not just started using metal detectors, the district has been using them to keep students safe for 12 years now.