In the wake of the shooting of UnitedHealthcare CEO Brian Thompson, Fortune 500 health care companies are in the spotlight for their practices. As people call into question the ethics and motivations of health care companies, Wendell Potter, former vice president for corporate communications at Cigna, penned a guest essay in the New York Times revealing what led him to leave the company in 2008.

“I left my job as a health insurance executive at Cigna after a crisis of conscience,” Potter wrote.

A push for ‘consumerism’

Potter revealed that his perspective on the company began to shift in 2005, when Cigna—one of the largest health insurers in the country—put forward an initiative focused on “consumerism,” which he says aimed to push more health care costs onto patients before their insurance coverage kicked in.

It was his job to develop a public relations campaign to lobby reporters and politicians to see Cigna’s new policy as “the long-awaited solution to ever-rising insurance premiums,” Potter wrote.

“But through my own research and common sense, I knew plans requiring significant cost sharing would be great for the well-heeled and healthy—and insurers’ shareholders—but potentially disastrous for others,” he said.

Prioritizing ‘profits over people’ firsthand

Potter described that as Cigna and other health insurance companies raised the costs of their plans—leaving customers with higher deductibles to reach before coverage would kick in—he grew uncertain of his role at the company.

It was an “impromptu visit” to a free health clinic at a fairground in Virginia near where he grew up that opened his eyes to the tangible issues with the American health care system.

“I witnessed people standing in lines that stretched out of view, waiting to see physicians who were stationed in animal stalls,” Potter wrote. He spoke to the clinic workers, who told him that of the thousands of people who came to the three-day clinic each year, some did have health insurance, but simply could not afford to cover their out-of-pocket costs.

“I was forced to come to terms with the fact that I was playing a leading role in a system that made desperate people wait months or longer to get care in animal stalls, or go deep into medical debt,” Potter wrote.

UnitedHealthcare CEO shooting brings insurance issues to the forefront

Potter’s essay comes in the aftermath of the murder of a prominent health insurance CEO, which spurred widespread outcry over consumers’ frustration with medical debt, denied claims, high deductibles, and inadequate coverage is being discussed now more than ever.

“The tragic assassination of the UnitedHealthcare chief executive Brian Thompson has reinvigorated a conversation that my former colleagues have long worked to suppress about an industry that puts profits above patients,” Potter wrote.

Earlier in Potter’s career, premiums and deductibles were not as costly—and insurers were not as aggressive, he said. Over time, however, pressure grew from investors to spend less on paying out patients’ claims. Now it is more difficult to get a claim approved—a process, he said, that “forces patients and their doctors through a maze of approvals before getting a procedure, sometimes denying them necessary treatment.”

The catalyst for Potter’s resignation was exactly that—Cigna’s denial of necessary treatment for 17-year-old leukemia patient Nataline Sarkisyan. He called it the event that “contributed most to my decision to walk away from my career.”

Her scheduled liver transplant was postponed at the last minute after Cigna declined to pay, claiming she was “too sick for the procedure,” Potter said.

In another last-minute decision, Cigna decided to pay—but it was too late. She died a few hours after they changed their mind, he wrote.

“As a father, I couldn’t imagine the depth of despair her parents were facing. I turned in my notice a few weeks later,” Potter wrote.

“I could not in good conscience continue being a spokesman for an industry that was making it increasingly difficult for Americans to get often lifesaving care,” he said.

When Fortune reached out to Cigna for comment, it responded with the following statement: “The world, healthcare, and our company have each evolved massively since Mr. Potter worked here almost two decades ago. He offers unsubstantiated claims and cites unnamed individuals with a self-interested goal that we can only presume is to sell books. His opinions do not reflect our company, commitment, and our focus on supporting the health of our customers and patients. We are constantly working to improve our support for patients and their care, and we are committed to doing our part to build a more sustainable healthcare model for America.”