He had names of people willing to testify, names of people to investigate, and exact locations of where to look. All of which he offered in a scif in accordance with the requirements of his clearance level. As soon as they get approved for the scif, then they'll see very quickly if he was full of shit or not.
Are you seriously asking why they didn't immediately have every bit of information and then immediately act on it? These things take time. There are very specific procedures that have to be followed.