Sandy Hook Gunman Obsessed With Columbine The gunman who carried out last year's Connecticut school shooting was obsessed with mass killings, investigators have said. Twenty children and six adults were killed by Adam Lanza on December 14 but his motive may never be known conclusively. State Attorney Stephen Sedensky III said there was no clear indication why the 20-year-old gunman chose Sandy Hook Elementary as his target other than the fact that it was close to his home. Twenty children and six adults were killed in the shooting at Sandy Hook The summary of the investigation said Lanza had an obsession with mass murders, in particular the April 1999 shootings at Columbine High School in Colorado. Lanza had significant mental health issues that affected his ability to live a normal life and interact with others but did not affect his mental state for the crimes. He "was undoubtedly afflicted with mental health problems," Mr Sedensky wrote. Adam Lanza committed suicide after killing 26 people at the school Yet despite a fascination with mass shootings and firearms, he displayed no aggressive or threatening tendencies. Some recalled that the shooter had been bullied but others, including many teachers, saw nothing of the sort. The mother of slain teacher Victoria Soto said in a statement that nothing could make sense of the shooting. Donna Soto said: "Yes, we have read the report, (but) no, we cannot make sense of why it happened. The shooting rampage sent shockwaves around the world We don't know if anyone ever will. We don't know if we will ever be whole again, we don't know if we will go a day without pain, we don't know if anything will ever make sense again. Lanza killed his mother inside their Newtown home before driving to Sandy Hook Elementary and carrying out the killings. He then committed suicide as police arrived. A timeline released with the report indicated that nearly six minutes passed between the arrival of the first Newtown police officer and the time officers entered the school. Demolition of the elementary school began in October The report said law enforcement officers were operating under the belief there may have been more than one shooter. Mr Sedensky released his report amid an ongoing court battle over the release of the 911 tapes associated with the shooting. The withholding of the recordings, which are routinely released in other cases, has been the subject of a legal battle between The Associated Press and Mr Sedensky before the state's Freedom of Information Commission. A Connecticut judge said on Monday he will listen to the tapes before ruling on whether they can be publicly released.