David Martinez, 20, of Bethlehem, was arrested for the rapes of a 14-year-old girl and a 17-year-old girl. Investigators say Martinez would prey on teenage girls who were lonely or had strained relationships with their families.
Police say Martinez would introduce himself to the girls over Facebook and ask for their phone numbers.
"He indicated that, daily, he would befriend new females and eventually, then, lured them into face-to-face meetings with him," said Northampton County D.A. John Morganelli.
After exchanging text messages, police say Martinez would take the girls out on dates, then allegedly take them back to his place and rape them.
Martinez was arrested after those victims each told their parents about the attacks, who then called police.
After his arrest, police say Martinez all but confessed to the rapes and indicated there were more victims out there.
"Asked why he became so aggressive toward these girls and he indicated that his hormones were 'out of control' and he believed was addicted to sex," Morganelli said.
So, on Wednesday, the District Attorney's office asked for any other victims to come forward.
"In addition to the victims we now know about, he would exchange information to females, including their cell phone numbers and their addresses," said Morganelli.
Next-door-neighbor Richard Davila says Martinez, who lived in that house with his mom and younger brother, seemed like a good person.
"Wow, I'm nervous. Honest to God, I'm a little shaken by that because the kid seems like a sweet kid," said Davila.
Anyone with information can call the Northampton County District Attorney's Office Tipline at 1-800-310-6545.