A Blackford County man has pleaded guilty to participating in an armed robbery back three years ago at a Muncie convenience store. The Star Press reports 22 year old Robert Rockwel pleaded guilty to aiding, inducing or causing armed robbery. Rockwell and two co-defendants were accused of robbing a clerk at gunpoint at the Riggin Mart, 4849 N. Broadway, on Jan. 22, 2019.