An alleged ISIS operative in the U.S. was plotting to kill George W. Bush, going so far as to travel to Dallas in November to take video around the former president’s home and recruiting help from a team of compatriots he hoped to smuggle into the country over the Mexican border, according to an FBI search-warrant application filed March 23 and unsealed this week in the Southern District of Ohio.

The FBI said it uncovered the scheme through the work of two confidential informants and surveillance of the alleged plotter’s account on the Meta-owned WhatsApp messaging platform. The alleged ISIS operative, based in Columbus, Ohio, said he wanted to assassinate Bush because he felt the former president was responsible for killing many Iraqis and breaking apart the country after the 2003 U.S. military invasion, according to the warrant.

The case shows how federal investigators continue to monitor threats from ISIS even as the group has been severely weakened by American intelligence and military operations in recent years. It also shows how the FBI, despite its claims of being prevented from investigating major crimes because of Meta and other tech providers’ use of encryption, has been able to work around WhatsApp security by using old-school policing with sourcing of informants and tracking the metadata they can get from the messaging company.