The robbers allegedly struck nine Wawas, 12 7-Elevens, and two A-Plus shops, according to the indictment, made public yesterday.

Sixteen of the stores in Philadelphia, five in Bensalem, one in Horsham and one in Abington. Masked men in the early morning hours between late August and early December last year robbed all 23 stores.

Local police earlier charged three of the four defendants in connection with more than a dozen of the stick-ups.

Federal authorities, intent on putting the robbers in prison for a long time, decided to adopt the case as part of a crackdown on roving thugs.

The four men are Desmond Stewart, 22, of Fairhill Street near Dauphin; Jhirmal Day, 21, of Marshall Street near Chew Avenue; David Jones, 20, of Large Street near Hellerman; and Hiram Malaret, 20, of Passmore Street near Loretto Avenue.

All four are in federal custody.

Their “take” from individual stores ranged from $40 to $1,700, court records indicate.

Two robbers at a time entered the stores.

The bandits wore bandanas or white T-shirt to cover their faces.

Prosecutors contend that the accused were armed at times with handguns but two of them told the FBI they had been carrying only BB guns, or just pretended to have a gun in hands wrapped by T-shirts.

Stewart allegedly admitted robbing at least 21 stores.

The three other defendants also admitted their involvement in the robbery spree, according to court records filed by Assistant U.S. Attorney Salvatore Astolfi.

Stewarts’s attorney, Michael Diamondstein, last night said his client maintains his innocence.

Diamondstein said it’s his understanding that the case against Stewart is based largely on the alleged “confession” that Stewart gave to police, but Diamondstein noted that this statement was taken from Stewart not long after he was released from a hospital, where he’d been treated for an epileptic seizure. The other defendants’ attorneys could not be reached for comment. Nor could Astolfi or FBI agent Joseph Majarowitz, the case agent.