Perris, California (CNN) Nearly two weeks after an emaciated 17-year-old girl called police to tell them her siblings were being held captive by their own parents, the Turpin family still has the world's attention.

But closer to home, neighbors, relatives and schoolmates are reeling from the allegations that David and Louise Turpin starved, tortured and shackled their 13 children -- ages 2 to 29 -- to their beds. They're now recalling every detail from their interactions with the family, and wondering how in the world they could have missed the warning signs.

Here's what they saw.

The neighbors caught glimpses ...

Salynn Simon, who lives across the street from the Turpin home in Perris, California, told CNN on Thursday that the neighborhood was still in shock.

"I just thought they were really private and that maybe they did most of their playing in the backyard," said Simon, who usually saw the family coming and going after nightfall.

Every now and then, Simon would approach the Turpin's front door to have her daughter sell the family Girl Scout cookies. "Louise would never open the door all the way," Simon remembered, but she would see children behind Louise jumping up and down because they were so excited for cookies.

Simon saw six of the Turpin kids at a community Christmas party a couple of years ago. She said the oldest was a boy, in his 20s, but she told him, "You look like you're a teenager, not in your 20s!" He just smiled and nodded, Simon said.

Julie Olah and Sharon Ontiveros, who also live in the neighborhood, said they were devastated by the news.

"It kills me," Ontiveros said. "It kills me."

Despite the fact that the world is asking how the neighbors didn't see any warning signs, the residents have tried to watch each other's backs, Olah told CNN. "So, when people sit there and try to tell you that, you were monsters, they don't understand the whole situation that was going on here."

The neighborhood has put together 13 large duffel bags with toiletries, hand-crocheted blankets, toys and "all the necessities," Ontiveros said, choking up. They hope to give the bags to the children when they're released from Child Protective Services.

"We're doing this with love in our hearts," Olah said, "just to let them know that we do care about them."

... and schoolmates noticed strange behavior

Last week, a former classmate of one of the Turpins' daughters, shared his memory of "a frail girl" who "often wore the same purple outfit."

The girl was "often made fun of by the other third graders because her clothes would sometimes look as though they had been dragged through mud," the classmate said in a Facebook post. The writer remembered how she smelled like feces, and how classmates scoffed when a teacher asked her to throw away a scrunchy fashioned out of "a discarded tin foil wrapper from an old Hershey's bar."

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While most of the Turpin kids were apparently home-schooled, one of the older boys attended classes at Mt. San Jacinto College and was on the honor roll in the fall of 2015 and spring of 2016, a spokeswoman confirmed to CNN.

Angie Parra, a student there, told KNBC she remembers the "sweet, but odd" young man in her music class who wore the same clothes every day and didn't make eye contact. She remembers how "famished" he was at a school potluck, saying that he scarfed down food, KNBC reported.

"He stood by the table and didn't sit down," Parra said. "He literally ate plate after plate after plate."

"I could see sadness in his face," she added.

Even family members were surprised

The Turpins' relatives said they were also in the dark, and recounted being rebuffed when they tried to have a relationship with the family.

Elizabeth Flores, Louise's sister, told ABC's "Good Morning America" that she pleaded with her sister to let her see her nieces and nephews, even over Skype. But they never let her.

"When that happens for 20 years, and it was before the kids even were there, you don't think it's abnormal," Flores said. "If it had been like two years ago that she cut us off, then we might think, wow, something's not right. But this has been going on before they even had children."

Once, Flores said, their father tried to surprise Louise with a visit. After he bought a plane ticket, Louise called and "told him not to come."

Flores even lived with the family for a few months while she was in college, years ago, when the Turpins had just a few children. "I thought they were really strict," Flores told GMA, "but I didn't see any abuse."

Another of Louise's sisters told NBC's "Today" show she was concerned about how skinny the kids were, but her sister would just "laugh it off."

"Well, David's so tall and lanky," Teresa Robinette remembers her sister saying. "They're going to be like him."