Kevin Federline was being tailed in the final weeks of his marriage to Britney Spears to investigate how close he had become to certain Las Vegas call girls, according to a source.
Of interest was a specific weekend not long before his wife filed for divorce on Nov. 7. But it seems K-Fed's stalkers didn't get what they were looking for.
"Prostitution is legal in Nevada, so it's no big deal to say he was 'partying' with them at a club," says one night crawler. "Also, there's no way to prove he even knows what they do for a living."
The investigator was paid for by a celebrity mag, adds the snitch. Federline's reps did not comment.