The man who attempted to breach the FBI field office in Cincinnati on Thursday failed thanks in part to poor planning, rapid response and the building’s bullet-resistant glass.

The suspect, who media reports identified as Ricky Walter Shiffer, was subsequently shot and killed by police on Thursday afternoon following a chase and a prolonged standoff, according to the Ohio State Highway Patrol (OSHP).

The incident began around 9 a.m. when Shiffer tried to attack the FBI Cincinnati’s visitor screening facility. According to a post on the social media platform Truth Social, which Shiffer frequented, Shiffer failed to breach the facility after an alarm sounded and the quick response by special agents.

“Well, I thought I had a way through bulletproof glass, and I didn’t,” Shiffer posted on Truth Social under the tag @RickyWShifferJr. His account has since been deleted. “If you don’t hear from me, it is true I tried attacking the F.B.I., and it’ll mean either I was taken off the internet, the F.B.I. got me, or they sent the regular cops.”

After the failed attack, Shiffer, armed with what officials and media reports say was a nail gun, fled the scene and headed north on Interstate 71. His vehicle was promptly spotted by a state trooper who attempted a traffic stop. Following a pursuit, Shiffer exited onto State Road 73 and ultimately stopped on Smith Road, where he exchanged fire with officers.

A long standoff ensued. The OSHP attempted non-lethal tactics to end the standoff, but Shiffer attacked the police, and the two parties engaged. Shiffer was pronounced dead at the scene around 3:40 p.m., the OSHP said.

Shiffer’s admission about the effectiveness of “bullet-proof” glass is no surprise. Bullet-resistant glass — no glass is bulletproof — is designed to withstand one or many rounds of bullets depending on the weapon and thickness of the glass. The glass is designed to reduce the velocity by absorbing the energy from the bullets. The purpose of the glass is to slow down an attacker from gaining entry with a gun or deterring them entirely, as was the case here.

Many bullet-resistant glass options are on the market. Armoured One, for instance, offers several glass options, including shooter attack glass and fire-rated attack glass. This glass was designed by active shooter experts and is military and police-grade, according to Armoured One.

In an effort to prevent an individual from entering a building with the intent to do harm, the ASTM F12 Security Committee developed a new ASTM International document, Standard Test Method for Forced-Entry-Resistance of Fenestration Systems After Simulated Active Shooter Attack.

The purpose of the universal standard is to provide school districts and businesses with a range of high-performance products to add additional protection.

“This standard should yield a good selection of accessible high-performance products that, when incorporated properly, may add a highly functional layer of protection for schools,” says Julia Schimmelpenningh, technical engagement manager for Eastman Chemical Co. in Springfield, Mass., laminating technical liaison for the association’s Fabricating Committee and a member of the school security task group. “The goal is to help minimize the number of injuries or fateful occurrences by deterring active shooter scenarios.”