He was part of a 22 person international mission to investigate attacks in the region.
The two departments formed a task force in June to investigate the attacks.
I'm investigating the terrorist attacks of this afternoon and I need to ask you a few questions.
It has allowed us to investigate and prevent attacks.
Kean would later lead the commission investigating the attacks of September 11, 2001.
In the last 10 days, two men have been charged with lying to the grand juries investigating the attacks.
He said the federal prosecutor's office, which usually investigates terrorist attacks, had taken over the inquiry.
There has been a lot of attention devoted to the memorial at ground zero, and to the independent commission to investigate the attacks.
Sirleaf also ordered the country's security forces to investigate the attacks and prevent further violence.
The research also shows that continuing to investigate attacks on statistical filters is worthwhile.