Riot Games is the latest in a recent series of developers taking on the makers of bots used to cheat in game. Riot has filed suit against LeagueSharp, a third party program for League of Legends that automates game play. According to Kotaku, Riot attempted an out of court settlement, but LeagueSharp representatives never responded to the outreach.
The papers filed in California, USA also indicate that LeagueSharp "disseminated personal and non-public information about a Riot employee, threatened that employee, and posted offensive comments on the employee's social media." Riot is suing for copyright infringement and for compensation for development dollars spent to block the application and to remove hacks from League of Legends.
In recent months, Blizzard Entertainment, Kakao Games and now Riot Games have filed lawsuits against bot and other third party software makers. To date, none of the legal proceedings have been resolved.
You can check out the court filing here and read more about the lawsuit at the link above.