AUSTIN — A biker shootout in Waco, Tex., that left nine people dead and nearly 20 wounded in May has resulted in 106 felony indictments, and Central Texas prosecutors say more indictments are likely in the protracted investigation.

A total of 177 people were arrested in the shootout on May 17 at a Twin Peaks restaurant in Waco, and the McLennan County District Attorney Abel Reyna served noticed that his office was poised to seek indictments against as many 71 others who were not named in the first round of indictments returned by a grand jury Tuesday.

“This is just the beginning of what is an ongoing, continuing investigation,” Mr. Reyna wrote in a post on Facebook announcing the indictments. “Eventually, all 177 cases will be put before this McLennan County grand jury.”

The indictments charged the defendants with engaging in organized criminal activity, and initial responses from defense lawyers suggested that they were prepared to vigorously fight the accusations in court.