UPDATE WEDNESDAY, SEPT. 18: Logan Mott had pleaded guilty to second degree murder.
The Florida State Attorney's Office released new evidence in the Logan Mott case Wednesday.
Prosecutors said the teenager killed and buried his grandmother in the backyard of his father's Neptune Beach home in Nov. 2017.
The evidence includes two videos and one audio recording believed to be of the teenager.
The video appears to show the teen with his face covered and speaking in a Russian accent.
In the video, the teen pretended to be the host of a Russian propaganda radio show.
"Comrades, it is your time. Rise with us. Let us overtake the bureaucracy that has corrupted America. Let us make America great again," the teen said in the video.
Mott said he was the lead propagandist of the "UCOA" organization, which he said stands for United Comrades of America, and called for others to join.
"Join the UCOA and together we will be the voice for all those suffering," Mott said.
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Court documents revealed Mott told friends he was from Russia and wanted to go back. The report also said he said he was secretly a spy.
According to prosecutors, Mott's Instagram page had mostly community propaganda material.
He's due in court Jan. 31 for a pretrial hearing.
Jury selection in the case is July 22.