SANTA CLARITA (CBSLA) — Authorities say have checked out several threats of violence against schools in Santa Clarita, even as the community grieves two students killed in a shooting at Saugus High School last week.

Los Angeles County sheriff’s investigators say they have not found any of the social media threats against Santa Clarita schools to be credible, including one that vaguely referred to Monday’s date. However, there will be an increased presence of law enforcement at schools, which will reopen Monday for the first time since Thursday’s shooting.

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Investigators say 16-year-old Nathan Berhow walked into the quad of Saugus High School Thursday before classes started and shot five people before turning the gun on himself. Gracie Anne Muehlberger, 15, and 14-year-old Dominic Blackwell died of their injuries. Berhow died Friday.

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All schools in the Hart Union High School District were closed Friday. All of the district’s schools will reopen Monday, except for Saugus High School, where classes will resume after the Thanksgiving break.

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Students who abandoned their belongings at Saugus High School immediately after the shooting were being allowed to pick them up from 10 a.m. to noon Tuesday.