New photos show the stomach-churning conditions that California “hell house” parents David and Louise Turpin subjected their kids to while living in Texas nearly two decades ago — suggesting their alleged abuse of their own children may stretch back for years.

When the Turpins lost their Fort Worth, Texas, home to foreclosure in 1999, the new owners, the Anderson family, thought the grime-caked floors and scratches on the backs of doors must have come from animals. But they’re reconsidering that after hearing Monday’s allegations that the Turpins kept their 13 children, ages 2 to 29, as prisoners in their squalid California home, CBS reports.

Photos taken right after the Turpins left the Texas home in 1999 show windows boarded up and walls covered in filth.

The Turpins’ 17-year-old daughter escaped their squalid Perris, Calif., home Sunday to alert authorities she and her siblings were being underfed and held there against their will.

Authorities thought she was only 10 due to her small stature, which officials say was likely caused by years of malnourishment. Even the older kids, the oldest of whom is 29, look like teenagers, suggesting they missed nutrition during crucial growth periods many years before their liberation this week.