Investigators said Hatziefstathiou was not new to criminal activity or racist behavior. In May 2015, they said, he used the online escort website Backpage to call escorts for his unsuspecting neighbors, then called 911 to report “suspicious vehicles" when the women appeared. Later, authorities said, he called the escorts with threats and racist remarks. The next year, officials said, he began recording himself making prank calls, and once called a hospital patient and yelled anti-Semitic comments.