After being taken into custody, Terrell told reporters he "just went into a classroom and shot the guys". He then reportedly made a full confession to investigators, saying he had planned an attack for some months. In subsequent statements requesting search warrants from a court, lead investigator Detective Brian Koll of the CMPD wrote Terrell "stated he had been planning this shooting for several months and described to detectives where and how he obtained the firearm, research he had conducted on mass shootings, and how he chose this location." In his confession, Terrell reportedly referenced the Sandy Hook Elementary School shooting, which police sources said he had "researched" at length. According to the same sources, he had gone to a shooting range to practice and had "at least 10 magazines." Dressed in black, he took the light rail to campus on the day of the shooting, carrying a backpack; CMPD investigators intended to review available security footage along the line. Terrell told investigators that he had entered the Kennedy Building with the intention of shooting others; before attacking, he loaded his weapon in a restroom near the classroom. He reportedly chose his victims at random with no specific target intended. According to police search warrants, he informed investigators he had used his Samsung cell phone to record a video of the shooting.