Related על חגיגה 3:6

If tax collectors entered a house and wrote on the outside [that] everything that is in the house is [ritually] pure, they are believed as to the purity of [articles involved in] the purification rite [of the red heifer], but they are not believed about the purity of Terumah, and in Jerusalem they are believed as to the purity of all the consecrated utensils but not about Terumah, and during the season of the pilgrimmage festival, [they are even believed] about Terumah. One who buys utensils from am ha'aretz skilled craftspersons, and one who sells utensils to am ha'aretz skilled craftspersons are believed about the purity of [articles involved in] the purification rite, but are not believed about the purity of Terumah.

If tax collectors entered a house, the house is unclean. If a Gentile was with them they are believed if they say, "we did not enter" but they are not believed if they say "we didn't touch anything." If thieves entered a house, only that part in which the feet of the thieves have stepped is unclean. And what do they cause to be unclean? Food and liquids and open earthenware, but couches and seats and earthenware that have tightly fitting covers remain clean. If a Gentile or a woman was with them, all is unclean.