WashingtonAt 19, Nikolas Cruz is not old enough to order himself a beer, but under Florida laws, he can buy a military style assault rifle legally.A day after he allegedly killed 17 people with an AR-15 in a high school in Florida, the United States was grappling with questions about easy accessibility to guns — especially military style firearms —, the alleged shooter’s “disturbed” mental health and red flags that authorities missed.The police said Cruz had confessed that he entered the school with the military style semi-automatic assault rifle (AR-15) and “began shooting students in the hallways and on the school grounds”. He also had “additional loaded magazines” in his backpack and intended to kill more but escaped by blending in with fleeing students.A frustrated and angry Lori Alhadeff, whose daughter Alyssa (14) was among the 17 people killed, was seen yelling on CNN channel, “President Trump, please do something! How do we allow a gunman to come into our children’s school? How do they get through security? What security is there?”“The gunman — a crazy person — just walks right into the school, knocks down the window of my child’s door and starts shooting. Shooting her! And killing her!”“I just spent the last two hours putting (together) the burial arrangements for my daughter’s funeral, who’s 14!”APStudents grieve during a vigil at Pine Trails Park for the victims of the Wednesday shooting at Marjory Stoneman Douglas High School in Parkland, Florida on Thursday.Alhadeff could have been speaking for the rest of the country, or at the least the section which has for long advocated gun law reforms, even some basic common sense changes like background checks on buyers to deny criminals and those with mental health issues access to arms.But gun controls have been foiled by the powerful National Rifle Association (NRA), which leads the gun lobby, even after the shooting of 26 people at Sandy Hook elementary school in Connecticut in 2012, including 20 six and seven year olds.The NRA and congressional Republicans even shut down government research on gun violence — to study and determine reasons behind it and find ways to prevent them — in the late 1990s, arguing it promoted gun control.Addressing the country on Thursday, President Donald Trump, who is a supporter of gun rights and keenly conscious of his political base’s antipathy to gun law reforms, spoke of the need for making schools safe and paying more attention to mental health issues. But, critics noted, he did not mention guns even once, or address demands being raised, again, for common sense gun laws reforms.In a tweet before the address, Trump focussed on the shooter’s mental health. He was “mentally disturbed”, he said, referring to a picture that is emerging of Cruz as a disturbed man, called “weird” and “violent” by people who knew him, his neighbors, past and present friends.Cruz had lost both his parents, and after his mother passed away in November, he was taken in by a family whose son went to the same school. But Cruz was expelled a year ago for disciplinary issues and had enrolled in an adult education course at the suggestion of his adoptive family.There have been suggestions there were red flags such as his postings on social media about becoming a “professional school shooter” that were missed. But the FBI, which was tipped off about it in 2017, has said there was not enough information on “the time, location or the true identity of the person who made that comment”.There had been other red flags such as frequent run-ins with the law.A white supremacist group, Republic of Florida, had claimed Cruz was associated with it, according to Anti-Defamation League, which tracks hate groups, which has spoken to a leader of the group. Cruz had taken part in shooting exercises held by the group for its members.But the Republic of Florida, whose claims have not been confirmed by authorities, denied it had anything to do with the shooting or that it had ordered Cruz to carry it out.The Florida massacre was the 30th mass shooting in the United States this year, following 346 in 2017 and 383 in 2016, according to gun violence trackers, who have also said there have been 18 school shootings in 2018.