False alarm it seems. It was just like enceledus said...
I read about it earlier. It was a bacteria found here on earth (in a lake), but it's dna had arsenic in it instead of phosphorous. All known life on earth has phosphorous as well as oxygen, hydrogen, nitrogen, sulfur and carbon. What they found did not have phosphorous, but arsenic.
The assumption could be made that this bacteria is extraterrestrial.
...except it's not like they suspect this actual microbe is extraterrestrial, but the fact that it can substitute phosphorous with arsenic means life can be more diverse than what has been assumed before, which heightens the possibility of extraterrestrial life.