The US President's accused the agency of spending "too much time" trying to prove Russian collusion with his election campaign ahead of the 2016 presidential race.

Very sad that the FBI missed all of the many signals sent out by the Florida school shooter. This is not acceptable. They are spending too much time trying to prove Russian collusion with the Trump campaign - there is no collusion. Get back to the basics and make us all proud!

— Donald J. Trump (@realDonaldTrump) February 18, 2018

The agency acknowledged that agents had failed to investigate.

Meanwhile, it has emerged that Cruz was investigated by the state's child welfare agency after posting Snapchat videos showing himself cutting his arms and speaking of his intention to buy a gun.

According to records from the agency, obtained by the Miami Herald, the 19-year-old uploaded the self-harm clips to the social media app in September 2016.

The Florida department of children and families' abuse hotline was alerted to the footage, with Cruz having been listed as a victim of "alleged medical neglect and inadequate supervision" on the part of his adoptive mother, Lynda Cruz, who died last year.

According to the agency's subsequent investigation, Cruz - who suffered from depression - was planning to "go out and buy a gun" and had placed "hate signs" on his book bag.
One of them was a Nazi symbol and another was a racist message.

An assessment of his mental health found his depression "impaired his ability to cope with the demands of everyday life without the use of medication", and that he sometimes "lacked the motivation" to see to his own welfare.

The latest revelations about Cruz's history came as thousands gathered at an anti-gun rally at Fort Lauderdale in Florida, some 25 miles from the school where 17 people were killed by Cruz on Wednesday.

Among those who attended on Saturday were survivors from the attack, which happened at Marjory Stoneman Douglas High School in Parkland.

One youngster, Emma Gonzalez, used the platform to call out Mr Trump over the $30m his election campaign received from the National Rifle Association (NRA) in 2016.
"To every politician taking donations from the NRA, shame on you," she cried, before prompting the crowd to chant in turn: "Shame on you! Shame on you!"

More protests over US gun control laws are still to come, with the Network for Public Education and the American Federation of Teachers calling on students, teachers and administrators to organise demonstrations for April 20 - the anniversary of the 1999 shooting at Columbine High School in Colorado.