A Higher Regional Court in Germany has confirmed the legality of an undercover investigation.
The ruling follows a 2013 investigation by German animal rights organization Animal Rights Watch [ARIWA].
Footage the group obtained from one of the largest pig breeding farms in Germany, (Van Gennip Tierzuchtanlagen GmbH) revealed violations of animal welfare codes, resulting in extreme cruelty.
Although criminal charges against the farm's operators were dropped, the investigators were charged with trespass.
They were found not guilty at the original trial - which then went to appeal. Again, they were found not guilty.
During a revision hearing at the end of last month, The Higher Regional Court of the federal state of Saxony-Anhalt in Germany acquitted the three defendants - confirming the two previous verdicts.
According to leading international animal protection agency Animal Equality: "So-called farmed animals endure unbearable agony in fattening farms and slaughterhouses.
"Without the exposure of animal welfare violations by undercover investigators, their suffering would never be known to the public.
"At Animal Equality we celebrate this verdict and hope it sends a clear message: Compassion is not a crime. Animal cruelty must continue to be revealed."