The ATP and WTA notified players in a memo that the FBI would be onsite at the BNP Paribas Open in Indian Wells to monitor social media abuse.

Sloane Stephens is one of several tennis stars who’s spoken out about being the target of hateful messages and threats. In a post to her Instagram story, Stephens documented the online abuse she received following her loss at the US Open, sparking a conversation about the prevalence of social media threats.

The BNP Paribas Open is set to begin on Monday and run through Oct. 17.