Sanford police say the knife attack at Family Dollar was part of an “ongoing fight.”

A knife attack Sunday at Family Dollar in Sanford “may have been the result of an ongoing dispute between the parties,” Sanford police said Wednesday.

Police made this statement after reviewing the video footage, adding: “It remains unclear what the fight was about or whether a specific incident led to it.”

According to Sanford Police Maj. Mark Dyer, Robert Wilson, 59, of Sanford was stabbed at the Family Dollar at Midtown Mall at approximately 10:02 p.m.

When officers arrived, they found Wilson on his knees while bystanders helped stop the bleeding, Dyer said Monday morning.

Wilson was taken to Maine Medical Center in Portland, where he was treated for stab wounds to his back and left side. Dyer said he was in stable condition as of Monday.

The suspect remained at large on Monday. Dyer said he had long hair and was wearing blue jeans, a backwards hat and a multicolored hooded sweatshirt, noting that it was neither tie-dyed nor camouflaged.

He was last seen heading north from the Midtown Mall.

Police initially said the suspect may have stolen a backpack, but said Wednesday there was “no evidence that the backpack in question was stolen.”

Police said they were looking for witnesses and a man who “may have an eye injury and could provide important information that could help us better understand what happened.”

Anyone with information about the stabbing can contact Sanford police at 207-324-3644.