Polymarket says its surveillance systems can identify anomalous trading as the U.S. midterm elections approach.The company uses blockchain analytics, machine learning and trade surveillance to detect potentially malicious activity.Polymarket says it has referred more than 100 cases to law enforcement, including suspected trades involving sensitive government information.The company says its controls block the vast majority of U.S. users from accessing its international platform under its 2022 CFTC settlement.