A string of six armed robberies over the last two days – four of them taking place in or near Petworth - have left one man in the hospital and at least seven victims lighter in the pockets. Three of the robberies took place Thursday morning and three took place early this morning. One of the robberies reportedly took place at knife point, and two of the robberies took place at gunpoint. MPD says it is investigating to determine whether the robberies are related.