Many of these students have been disciplined, but the district isn't saying to what extent. Police, meanwhile, are sorting through the evidence. They've confiscated over a dozen phones.
Brentwood police say the sharing of sexually explicit photos via text messages involved 16 students at four schools: Adams Middle School, Edna Hill Middle School, Bristow Middle School and Excelsior Middle School.
Investigators say it started out as girls voluntarily texting photos of themselves to male students, which then got carried away after some of those images were exchanged with other students.
"What was being described were pictures that were taken of perhaps body parts and so at that point that's when the principal contacted the police," Brentwood Union School District spokesperson Dana Eaton said.
Soon after Brentwood police began investigating, they realized the sexting turned into blackmail. They say a male student threatened to post a sexually explicit picture of one of the girls.
"A male involved threatened to use a photo that he acquired of the female victim," Brentwood Police Sgt. Walter O'Grodnick said. "He threatened to use that photo if she failed to engage in sexual misconduct with him."
Police say the sexual activity took place in one of the bathrooms at Adams Middle School. Investigators say that boy will be arrested soon on a felony charge.
Parents of the school were notified of the incident by email.
"I'm shocked really that, really that it went so far and they're doing things like that on campus, you know, really that the act that took place on campus," parent Tiffany Hom said.
"It affects everyone, the victim of course and then themselves for their future and their parents because this isn't something that their parents taught them," parent Aomalu Letuligasenoa said.
The other boys will likely be arrested as well on charges of distributing child pornography, but police say they are still working on collecting evidence. They're extracting the photos from more than dozen phones, a process that could take days if not weeks.