In the summer of 2014, Lee-Anne Walters — a mother of four in Flint, Michigan — noticed something strange. Guests in her swimming pool developed “scabies-like” rashes. Her family’s hair was thinning and falling out. One of her 4-year-old twin sons, Gavin, was not growing. He developed speech problems. Her husband developed abscesses.

There were “all these different things,” but “we weren’t putting it together,” she said.

By fall, when water in her faucet began running yellow and brown, Walters knew: The water wasn’t safe.

Though it wouldn’t be confirmed until much later, she was right. The city’s water was heavily contaminated by lead, which studies have linked to chronic and irreversible health problems, especially for children, including learning disabilities, intellectual disabilities, stunted growth, seizures and even death.

Despite the severity of contamination and many warnings, it would take many more months before officials did anything. The lack of response was so egregious that The New York Times editorial board described it as “depraved indifference,” suggesting there was “little doubt” that a richer, whiter community would ever have to face such negligence.

“If I was a parent up there, I would be beside myself,” President Barack Obama said during a visit to Michigan earlier this month.

But amidst all the hand-wringing, two questions are still largely unanswered by officials: How could this go on for so long? And who was ultimately responsible?