LITTLETON, Colo. (AP) - A Colorado community changed forever by the attack that killed 13 people at Columbine High School moved ahead Thursday with ceremonies marking the anniversary of the tragedy while awaiting more details on what led a Florida teen 'infatuated' with the shooting to buy a shotgun and kill herself in the snowy foothills nearby. Many questions remained unanswered about 18-year-old Sol Pais, but a friend disputed the contention by authorities that she posed a threat. Adrianna Pete painted a complex picture of Pais, saying she was deeply troubled, lonely and often talked about suicide but was also brilliant, kind and a talented artist who loved to draw. Pete, 19, a college student in Carleton, Michigan, said she met Pais online two years ago through a mutual friend and quickly developed a friendship involving near-daily communication. They met in person twice, once when Pete traveled to Florida and once when Pais went to Michigan. Pete faulted authorities for overreacting in portraying Pais as a threat based on her activities before her death. 'She never threatened anyone,' Pete said. 'There are no credible threats and only assumptions that she was just because the word Columbine was included.' Pete said Pais had a weird obsession with the Columbine killers but that didn't mean she was planning an attack. The killers were 'someone she could relate to' because they were lonely, not because of their violence, Pete said. 'She would say I hate life, life sucks and that she was very alone,' Pete said. 'Then she told me she had it figured out with her parents before so I assumed like she was doing OK ... She actually posted about it a lot, wanting to die.' Two teenagers attacked Columbine on April 20, 1999, killing 12 classmates and a teacher before taking their own lives. They have inspired cult-like admirers, some of whom committed other mass shootings. The days surrounding the April 20 anniversary of the attack are always emotional for school alumni, their families and the suburban community of Littleton surrounding Columbine. Some survivors describe the experience as an 'April fog.' The manhunt for Pais and the resulting closure of schools added a new layer of anxiety, former Columbine principal Frank DeAngelis said Wednesday after the FBI declared the danger was over. A religious service Thursday night will begin three days of commemorative events themed 'Remember. Reflect. Recommit' leading to a day of community service projects and a ceremony Saturday at a park near the school. Pais' body was discovered Wednesday in the mountains outside Denver with what appeared to be a self-inflicted gunshot wound. Colorado authorities learned about Pais on Tuesday from an alarmed Miami FBI office that had interviewed people about her obsession with the Columbine shooting. Dozens of schools, including Columbine, locked their doors for several hours on Tuesday and even more closed altogether on Wednesday. More than 400,000 students returned to Denver-area schools Thursday, with visible police presence outside buildings. FBI officials declined Wednesday to discuss Pais' mental health or detail the comments she made indicating an 'infatuation' with the Columbine shooting. An FBI spokeswoman did not immediately respond to a request Thursday for more information on Pais' background or her Columbine-related comments that sparked a rapid law enforcement response. Officials at her Florida school district said they had no record of Pais being contacted by law enforcement or disciplined in school. Her family has not spoken publicly but worked with authorities this week. Pete described Pais as caring and thoughtful, someone who helped with her Spanish homework and sent her a pair of earrings when she was having boyfriend troubles. When they got together in Miami last summer, they went swimming at the beach, walked the boardwalk and played with stray cats. Almost daily, Pais walked to a store and bought a coffee energy drink. She was obsessed with them, Pete said. 'I believe she was just very mentally ill and had no one but me to confide in and a few people on the internet,' Pete said. FBI officials said Wednesday they were reviewing all of Pais' activity in recent weeks, including her social media accounts and other online writing. They confirmed that online material includes a blog featuring hand-written journal entries about the author's unhappiness and desire to die along with sketches of guns or knives. Pais did not make threats against a specific school but her history and purchase of a weapon immediately after arriving in Colorado merited a broad response, officials said. Pais arrived Monday and went directly to a gun store, where she bought a shotgun, authorities said. The purchase apparently followed the legal process, officials said. ___ Kennedy reported from Miami. Associated Press writers Ellis Rua in Miami Beach, Florida, and James Anderson, P. Solomon Banda, Colleen Slevin and Thomas Peipert in Denver contributed to this report.