Complex sentence: According to Andreas Pilsl, Chief of Police for Upper Austria, evidence suggests that the suspect acted alone and that he was been investigated in 2015 after police received anonymous tips, but that at that point "nothing was found that could indicate a radicalization".
Split into simpler sentences: According to Andreas Pilsl, Chief of Police for Upper Austria, evidence suggests that the suspect acted alone. He further stated that suspect has been investigated in 2015 after police received anonymous tips, but that at that point "nothing was found that could indicate a radicalization".