inconclusive
The investigation ended inconclusively.
Nitrates in food have been linked inconclusively with stomach cancer.
We spent over a year inconclusively reviewing how to overhaul the distribution system.

SMART Vocabulary: related words and phrases

Concluding and deducing
analysis
deduce
deduce something from something
deducible
deductive
diagnosis
draw
gather
hypothetico-deductive
impute something to someone
in the last/final analysisidiom
induction
inductive
non-deductive
put
put something down to something
put two and two together and make fiveidiom
put two and two togetheridiom
reason
syllogism

You can also find related words, phrases, and synonyms in the topics:

Uncertainty