The doctrine of the “fruits of the poisonous tree” states that the evidence (fruit) from an illegal search or seizure which is a tainted source (the tree), would also be tainted and hence, inadmissible.
Illustration: A police officer illegally breaks into a house belonging to a suspect (in an incident unrelated to any investigation) but stumbles upon a crucial piece of evidence (say, a blood-stained knife which looks like a murder weapon or a forged letter of credit). Now, there’s no doubt that this rather enterprising police officer has committed a crime (housebreaking/trespass, amongst others) but would the evidence seized still be admissible in a court of law? Or would it be termed what we lawyers call the ‘fruits of a poisonous tree’ and eschewed from consideration being inadmissible? Is it true that, even if something is admittedly stolen, it is still admissible in evidence?
There is nothing in the Evidence Act, 1872 forbidding the courts from looking at an illicitly obtained piece of evidence if it is otherwise relevant to the matter or goes on to establish the guilt or prove innocence. The Courts have time and again held that illegally or improperly obtained evidence is not per se inadmissible.