A shooting in El Cerrito that injured a man Tuesday was likely the result of a resident firing at a home intruder, according to police. At approximately 10:30 a.m., officers responded to a reported shooting in the 1800 block of Elm Street. Arriving officers located an injured man, later identified as 56-year-old William Nidever, a transient from the West Contra Costa County area. Nidever was airlifted to a trauma center for treatment of his injuries. The alleged shooter — the resident of the home — was detained. After an investigation, police believe the resident shot Nidever after he unlawfully entered the home. “The resident realized that Mr. Nidever was an unknown intruder and thought Mr. Nidever was armed with a weapon,” El Cerrito police said in a Tuesday afternoon release. “The resident feared for his life and shot at Mr. Nidever twice with a shotgun.” Investigators also determined that Nidever was not in fact armed with a weapon, but police said they anticipate bringing a criminal case to the Contra Costa County District Attorney’s Office for burglary. Police said during the initial response, Summit K2 school at 1800 Elm St. was placed on a precautionary lockdown. The lockdown was lifted as soon as the scene was secured.