Nikolas Cruz cut his arms on Snapchat and said he wanted to buy a gun in September 2016, more than a year before he was accused of killing 17 people in a school in Parkland, Florida, records obtained by the South Florida Sun Sentinel show.

The incident on the digital social network prompted an investigation by sheriff’s deputies and adult welfare investigators from the Department of Children & Family Services.

The documents provide further evidence that Cruz was a troubled teen who repeatedly went without help before he stalked the halls of Marjory Stoneman Douglas High School with an AR-15 rifle on Wednesday.