CHICAGO (CBS) — Police are investigating two violent robberies early Friday morning, and investigators believe the attacks might be connected.

The first happened around 12:30 a.m. in the Printers Row neighborhood. Police said a 34-year-old man was walking near Polk and Dearborn, when a group of five young men attacked him.

The men threw him to the ground and began beating him before stealing his backpack, cell phones, and other valuables. The robbers were last seen running toward the Red Line.

The victim was treated at the scene, but didn’t need to go to the hospital.

A little more than 30 minutes later, police responded to another robbery in the River North neighborhood.

A 21-year-old man told police an 18-year-old man snatched his cell phone from his hand near Rush and Superior. When the man ran off, the victim chased him, and was beaten by five other men, who also stole his money, police said.

Officers swarmed the area and arrested six suspects. A backpack also was recovered.

The victim was treated for facial wounds, but declined to go to the emergency room.

Police have said they believe the two robberies are related.

Area Central detectives were investigating.