A man accused of shooting a man leaving a Mountain View domestic dispute in the back of the head with a rifle early Tuesday told his family he “screwed up,” according to charging documents in the case.

Talon Draper, 19, was arraigned Wednesday on a first-degree assault charge in the shooting of 22-year-old Jermaine Twiley, outside an apartment complex on the 3400 block of Thompson Avenue. According to charging documents, Twiley -- who was rushed to a hospital but remains in critical condition -- underwent an emergency craniotomy, a procedure in which surgeons access the brain by temporarily removing a piece of bone.

Documents say Draper lived in a third-floor apartment with his mother and brother, who had fallen asleep while playing video games but were awakened shortly after midnight Tuesday by a domestic dispute between Twiley and his girlfriend next door. Numerous callers, including Draper’s family, reported the disturbance to police dispatchers; the girlfriend suffered minor injuries in the altercation, but police weren’t aware of them at the time.

“APD officers had responded and contacted the couple separately,” prosecutors wrote. “The female was uncooperative with police and refused to describe what happened or provide any information. Without more information, the officers left the area.”

The shooting occurred in the wake of a second disturbance between the couple, which Draper told police woke him up.

“According to neighbors, Twiley and his girlfriend started yelling at each other about an hour later,” prosecutors wrote. “The female was screaming and asking for someone to call 911.”

Draper went to the apartment’s front door, grabbing and loading a .22 long gun in his bedroom closet. The documents say that's when he saw Twiley running away; according to initial statements from APD, Draper had said Twiley reached down with his hands just before Draper opened fire.

“(Draper) yelled for Twiley to stop and fired his gun twice striking Twiley in the back of the head,” prosecutors wrote. “Draper went back inside his apartment telling his mother to call 911 because the male needed help and stating that ‘he screwed up.’”

APD spokesperson Jennifer Castro has described the case as an incident involving an intervention in a domestic-violence dispute, rather than a stand-your-ground incident. Police recommend that people who witness similar incidents call 911 rather than trying to personally intervene.