Noah Green, the man suspected of killing a cop in an attack outside the U.S. Capitol last week, was caught on camera buying a knife 90 minutes earlier, Daily Mail reports. Surveillance footage shows Green walking into a specialty knife shop around 10 minutes away from the Capitol and buying a 10-inch artisan knife that costed $300. He reportedly seemed “calm.” Less than two hours later, he allegedly rammed his car into a barricade outside the Capitol, then brandished a knife at officers, prompting one to fatally shoot him. One officer, William “Billy” Evans, died in the attack.

Green’s family expressed concern that he had been suffering suicidal thoughts, paranoia, and delusions. His brother previously said Green was “violently ill” the night before the attack. In March, Green posted online about being unemployed and in search of “spiritual guidance” through the Nation of Islam.