Fredrick Brennan, who founded but later distanced himself from the 8chan message board that has given encouragement and visibility to violent extremists, is facing arrest in the Philippines in a “cyberlibel” case brought by the site’s current owner.

An arrest warrant was issued Thursday in Pasig City, his lawyer, Alex Acain, told Rappler, a news site in the Philippines. Mr. Brennan is currently in the United States, and it was unclear on Thursday if he planned to return to the Philippines, where he lives.

The case stems from Twitter posts Mr. Brennan, who gave up control of 8chan in 2015, directed at Jim Watkins, who took over the site and also lives in the Philippines. Mr. Watkins, whose message board contains unapologetically racist material that has frequently cheered deadly violence, sued Mr. Brennan after tweets that referred to Mr. Watkins as “senile” and called the site’s moderators “incompetent.”

In the Philippines, cyberlibel is a criminal offense that can be punished with prison time.

In recent years, Mr. Brennan has repeatedly criticized the site and how it has been run. Several mass shooters, including those accused in shootings in Christchurch, New Zealand, and El Paso, had posted hate-filled screeds on the forum before their attacks, and been cheered on by the site’s users.