Shell casings with words written on them were found at the scene of the UnitedHealthcare CEO's death.

• According to NBC News, shell casings from the murder of UnitedHealthcare CEO Brian Thompson in midtown Manhattan had the words "deny," "defend," and "depose" written on them.
• The chilling words in the title of the 2010 book, "Delay Deny Defend," reflect the subtitle's claim that insurance companies often fail to pay claims and offer suggestions on how to address the issue.
• UnitedHealth Group's subsidiary, Thompson's company, is the largest private health insurance payer in the US and has faced criticism for its high rate of denying healthcare claims.

According to NBC News, law enforcement sources revealed that shell casings from the murder of UnitedHealthcare CEO Brian Thompson in midtown Manhattan contained the words "deny," "defend," and "depose."

The chilling words in the title of the 2010 book, "Delay Deny Defend," reflect the subtitle's claim that insurance companies often fail to pay claims and offer suggestions on how to address the issue.

The largest private health insurance payer in the United States, Thompson's company, has been the subject of controversy over its high rate of denial of health-care claims.

On Wednesday morning, a masked gunman with a silenced pistol shot and killed Thompson, 50, outside the Hilton Hotel in midtown. The shooter escaped on a bicycle into Central Park and is still at large.

A married father of two sons, Thompson, was walking into a hotel on West 54th Street for a UnitedHealth investor meeting when he was fatally shot.

At the scene, three spent shell casings and three live rounds were discovered.

This is developing news. Check back for updates.