Same universe as the Flinx stories.
The founding of the Humanx Commonwealth was not an easy process. In the second half of the 24th century diplomatic relations proceed cautiously between thranx and humans. But the insectlike beings are nearly forgotten with the sudden discovery of an ideal planet to colonize and the startling appearance of a new race of spacefaring aliens--the beautiful, glamorous Pitar.
Then tragedy strikes. The entire human population of the new colony planet is brutally slaughtered. Not a single clue remains to identify the executioners, but from a tiny inner moon comes a faint signal. On that insignificant chunk of rubble lies the key to the crime---if the humans can keep the witness alive long enough to tell . . .
Great space opera.