At a press conference Monday morning, Arapahoe County Sheriff Grayson Robinson revealed new details about the shooting at Arapahoe High School earlier this month, including one that indirectly ties the shooter to the school shooting at Columbine: Just before he shot and killed 17-year-old Claire Davis and committed suicide in his school's library, Karl Pierson went bowling.

Initially, there were rumors that Dylan Klebold and Eric Harris attended a bowling class before shooting 13 people to death at Columbine High School in 1999. Those rumors were later disproved—Klebold and Harris skipped their classes that morning—but the story's prevalence led to the title of Michael Moore's 2002 documentary about the shooting, Bowling for Columbine. Despite the connection, Sheriff Robinson said there was no direct evidence showing that Pierson was inspired by the Columbine shooters.

Robinson said Pierson "gave no indication that anything was amiss" before the shooting, which he described as a "very deliberate event" that was likely planned without any "direct or indirect co-conspirators." Robinson also gave a timeline of the shooting. From NBC News:

Upon entering the school on its north side, armed with a shotgun, machete, 125 rounds of ammunition and three Molotov cocktails, Pierson fired one round randomly into the hallway of the school before shooting a fatal second round that killed senior Claire Esther Davis, 17.

Pierson then fired another random shot before making his way into the school's library and media center. Robinson said Pierson then fired one round into the area surrounding the office of school librarian and debate team coach Tracy Murphy, believed to be his intended target.

He then ignited a Molotov cocktail in the center of the library, setting a fire that burned four book shelves and created a large amount of smoke. He then fired a fifth round and took his own life with a single gunshot to the head.

[Image via AP]