He said she was easily accessible on line but strangely elusive in person.
"I guess I wasn't paying attention," said Te'o in an interview with Katie Couric the week before.
"The bottom line is fraud works," said van Marter.
He said Tuisasosopo's love-stung story is the type of scheme often linked to 'easy money.'
"He would tell me he loved me, and he had feelings for me," began a woman we called "Ann" during an interview in 2010.
In less than three weeks,"Ann's" fake online love tricked her out of $11,000.
"I realized I was sending money to someone who wasn't there, that wasn't real," she said.
"They think they're smarter that everyone else. They don't think they're going to get caught. If they do they don't think the consequences will be significant. For some it's a challenge. It's fun," said van Marter.
The number and cost of cyber crimes has exploded in recent years.
In 2011 alone: The Internet Crimes Complaint Center received more than 300,000 complaints and U.S. victims lost more than $485 million.