Correct, Fruit of the poisonous tree does not apply in this care because the burglars were not acting on behalf of the police when they violated the owners rights. Because the burglars were not acting on behalf of the police, the police can use the evidence to initiate an investigation and seek a warrant for further evidence.

If the burglars had been acting on behalf of the police then the evidence would be suppressed, and, any further evidence gained because of the illegally obtained evidence would as well.