That first test was inconclusive. They could not pin down the source. But recently the loss rate increased and they repeated the test. There was some mention of it during yesterdays Commercial Crew press conferences. The source could now be traced to one russian module. As they mentioned it is now down from a needle in 7 haystacks to a needle in only 1 haystack. They will now begin searching with a leak detector.
As long as the leak rate does not increase dramatically, there is no risk for the ISS.