LINCOLN -- Arial">A 27-year-old man who was found injured on June 29 has died after being taken off life support. Lincoln Police Capt. Michon Morrow tells KFOR News David Mueller died some time Sunday afternoon. It's unclear what caused Mueller's head injury. Morrow says an autopsy is scheduled for Monday. A passer-by spotted Mueller on a sidewalk near 14th and Benton streets around 3:30 a.m. on June 29. Mueller's cellphone and wallet were missing, but Morrow says they're not certain that Mueller was robbed. Doctors told police they believe Mueller's injuries were more severe than what would have resulted from a fall. Morrow says this incident happened the same time as the assault on 20-year-old Nathan "Shane" Walton near 38th and "L." Walton died from his injuries last Tuesday. Morrow says at this point they DO NOT believe both of these cases are related.