LANCASTER (CBSLA.com) — A high school in Lancaster is being accused of leaving several special needs students out of the yearbook.

CBS2/KCAL9’s Jennifer Kastner spoke to outraged family members during Thursday night’s packed graduation ceremony at Quartz Hill High School.

READ MORE: Family Still In Shock After They Hired Home Improvement Contractor Via HomeAdvisor, Only For The Contractor To Smash Up Their Property

Daniel Escobedo’s family says the 22-year-old with Down Syndrome spent the past six years earning his high school diploma, only to be left out of the yearbook.

Older sister Marisela Escobedo says the school neglected to put the photos of more than a handful of special education program graduates, like Daniel, in the yearbook: “It infuriates me.”

READ MORE: Jacqueline Avant, Wife Of Music Executive Clarence Avant, Found Shot To Death In Beverly Hills Home Invasion

Principal Matt Anderson says two, possibly three, students were left out due to issues with a third party contracted photographer. He added that he didn’t know details about Escobedo’s case, but apologized if there were any unintended problems.

“I don’t think it was an honest mistake,” said parent Debra Newman, who believes the special education students are an afterthought for the administration. “They’re attending the school just like the regular ed, or neuro-typical children, so they should not be discriminated against. They should be included.”

The principal told Kastner the school will create an add-on page for anyone whose photo didn’t make it in the yearbook.

MORE NEWS: Biden To Announce COVID Testing Requirement For International Travelers, Insurance Reimbursement For At-Home Tests

Escobedo’s sister says she was contacted a few hours before graduation and offered a full refund for the yearbook, but with no explanation as to why.