The only people Juliette did not know were the three renters, who lived across the street. Kenneth made a remark that "three's a charm" like that might be the house he would have the verrat attack. However, two houses were attacked and according to the script, both of them were across the street. It was pretty specific, and it appears to me, that Kenneth didn't go with the original houses he asked Juliette about.
The best way to frustrate a cyberbully is to ignore him.