Juliette Kayyem, former assistant secretary for policy at the US Department of Homeland Security, told BBC Radio 4's Today programme that his background in technology may have helped him evade capture for nearly a week.
"This was someone who was studying how law enforcement and how these cities try to protect themselves, which is essentially they have lots of cameras around," she said.
"Now that we know a little bit about him - that he's a smart person, he went to great schools, he had higher degrees, he studied engineering technology, he was into electronic gizmos - some of it is beginning to make sense," Kayyem said.