(CNN) — On paper, it seemed like a fantastic deal. In 2017, the Chinese government offered to spend $100 million to build an ornate Chinese garden at the National Arboretum in Washington. Consisting of temples, pavilions and a 70-foot (21-meter) white pagoda, the project excited local officials, who hoped it would attract thousands of tourists each year. But when US counterintelligence officials began to investigate the details, they found numerous red flags. They noted that the pagoda would have been strategically placed on one of the highest points in the city of Washington, just 3 kilometers (2 miles) from the…