Japanese space officials have found intriguing dust-like particles inside the sample capsule from the asteroid probe Hayabusa, but whether they are actually pieces of an asteroid or contamination from Earth remains to be seen, Japan's space agency announced Tuesday.

The tiny particles were discovered after scientists opened the Hayabusa probe's sample container, which returned to Earth on June 13 after a seven-year journey to the asteroid Itokawa. Scientists began opening the capsule on June 24, officials with the Japan Aerospace Exploration Agency (JAXA) said.

"The fact is that the JAXA scientists found some particles in the sample container and the sample catcher," JAXA spokesperson Makoto Miwada told SPACE.com. [Photos of the asteroid probe's particles.]