A message left at the scene of an insurance executive’s fatal shooting — “deny,” “defend” and “depose” — echoes a phrase commonly used to describe insurer tactics to avoid paying claims.

The three words were emblazoned on the ammunition a masked gunman used to kill UnitedHealthcare CEO Brian Thompson, a law enforcement official told The Associated Press on Thursday. They're similar to the phrase “delay, deny, defend” — the way some attorneys describe how insurers deny services and payment, and the title of a 2010 book that was highly critical of the industry.

Police haven't officially commented on the wording or any connection between them and the common phrase. But Thompson's shooting and the messages on the ammunition have sparked outrage on social media and elsewhere, reflecting a deepening frustration Americans have over the cost and complexity of getting care.

“Delay, deny, defend” has become something of a rallying cry for insurance critics. The terms refer to insurers delaying payment on healthcare claims, denying claims and defending their actions.

“Delay, deny, defend” is also the title of a 2010 book by Jay Feinman that delves into how insurers handle claims.

UnitedHealthcare provides coverage for more than 49 million Americans and brought in more than $281 billion in revenue last year as one of the nation’s largest health insurers. UnitedHealthcare and its rivals have become frequent targets of criticism from doctors, patients and lawmakers in recent years for denying claims or complicating access to care.

Critics say insurers are increasingly interfering with even routine care, causing delays that can, in some cases, hurt a patient's chances for recovery or even survival.

Doctors and patients have become particularly frustrated with prior authorizations, which are requirements that an insurer approve surgery or care before it happens.

UnitedHealthcare was named in an October report detailing how the insurer’s prior authorization denial rate for some Medicare Advantage patients has surged in recent years. The report from the U.S. Senate Permanent Subcommittee on Investigations also named rivals Humana and CVS.

Insurers say tactics like prior authorization are needed to limit unnecessary care and help control spiraling medical costs.

Frustrations extend beyond the coverage of care. Expensive breakthrough medications to slow Alzheimer’s disease or help with obesity are frequently not covered or have coverage limits.