According to federal prosecutors, 19-year-old Alexander Hillel Treisman was arrested after plotting to assassinate Democratic presidential nominee Joe Biden.

Federal officials say Treisman had an interest in terrorist attacks and mass shootings and was stockpiling weapons, explosives, and ammunition.

In May, employees at a bank in Kannapolis, North Carolina, called police to report a suspicious white van in the parking lot. When police arrived, they discovered a 9mm handgun, explosive materials, books on bomb-making, and $509,000 in cash inside the van.

When deputies investigated Treisman’s devices they found a post with the caption, “should I kill Joe Biden?” Officials said that Treisman decided to follow through with the assassination plot, and he began to search for his address. Police say Treisman also began traveling around the country to buy firearms in different states. At one point, officials said that he stopped a Wendy’s in Delaware that was just four miles from Biden’s home.

Investigators also uncovered a massive trove of child pornography on eight different devices that Treisman was using. Authorities charged the teen with possession of child pornography, but he has not been charged over the alleged plot to assassinate Biden.