The Red heifer rite is one of the most memorable in the Torah, and has explicit instructions on how and by whom it is performed. As we can see it was designated for the priest (Kohen) to perform this ritual.
ד וְלָקַח אֶלְעָזָר הַכֹּהֵן, מִדָּמָהּ--בְּאֶצְבָּעוֹ; וְהִזָּה אֶל-נֹכַח פְּנֵי אֹהֶל-מוֹעֵד, מִדָּמָהּ--שֶׁבַע פְּעָמִים.
4 And Eleazar the priest shall take of her blood with his finger, and sprinkle of her blood toward the front of the tent of meeting seven times.
5 And the heifer shall be burnt in his sight; her skin, and her flesh, and her blood, with her dung, shall be burnt.
6 And the priest shall take cedar-wood, and hyssop, and scarlet, and cast it into the midst of the burning of the heifer.
7 Then the priest shall wash his clothes, and he shall bathe his flesh in water, and afterward he may come into the camp, and the priest shall be unclean until the even.
In verse 7 we are told that the priest will launder his clothes and bathe his flesh, but will remain unclean until evening. The bathing process is done in daytime, but he does not attain purity until evening.
This is quite explicit, and was practiced by the Kohanim until the foreign interference of the Rabbanites, who very likely did not have Jewish roots (many of the Pharisee rabbis were in fact foreign converts, most notably Shemaya and Avtalyon). This is also evidenced by the fact the genuine Kohanim of the 2nd Temple era were Sadducees, and the Pharisees did not have genuine Kohanim who would serve in the temple, Instead, they devised false methods to tamper with the Priesthood, the rituals and the Torah.
The Rabbinic body of literature has its first appearance in the Mishnah, which recounts how they dealt with all sorts of issues, including the Red Heifer. The aptly named Mishna “Parah” provides an account of how they went about achieving their ends, and how they falsely interpreted the Torah.
In Parah 3:7 we see:
לֹא הָיְתָה פָרָה רוֹצָה לָצֵאת, אֵין מוֹצִיאִין עִמָּהּ שְׁחוֹרָה, שֶׁלֹּא יֹאמְרוּ, שְׁחוֹרָה שָׁחֲטוּ. וְלֹא אֲדֻמָּה, שֶׁלֹּא יֹאמְרוּ, שְׁתַּיִם שָׁחֲטוּ. רַבִּי יוֹסֵי אוֹמֵר, לֹא מִשּׁוּם זֶה, אֶלָּא מִשּׁוּם שֶׁנֶּאֱמַר (במדבר יט), וְהוֹצִיא אֹתָהּ, לְבַדָּהּ. וְזִקְנֵי יִשְׂרָאֵל הָיוּ מַקְדִּימִים בְּרַגְלֵיהֶם לְהַר הַמִּשְׁחָה, וּבֵית טְבִילָה הָיָה שָׁם. וּמְטַמְּאִים הָיוּ אֶת הַכֹּהֵן הַשּׂוֹרֵף אֶת הַפָּרָה, מִפְּנֵי הַצְּדוֹקִים, שֶׁלֹּא יִהְיוּ אוֹמְרִים, בִּמְעֹרְבֵי שֶׁמֶשׁ הָיְתָה נַעֲשֵׂית:
If the cow refused to go out, they may not take out with it a black one lest people say, "They slaughtered a black cow" nor another red [cow] lest people say, "They slaughtered two." Rabbi Yose says: it was not for this reason but because it is said "And he shall bring her out" by herself. The elders of Israel used to go first by foot to the Mount of Olives, where there was a place of immersion. The priest that was to burn the cow was (deliberately) made unclean on account of the Sadducees so that they should not be able to say, "It can be done only by those on whom the sun has set."
We learn that these Pharisee “elders” would deliberately defile the Kohanim, and thus invalidate them from the ritual. This was to negate the meaning of the Torah in Bamidbar 19:7, which says the priest will remain unclean (impure) until sunset. The new interpretation of the Pharisees was that the bathing itself will purify the Priest from the contact with the Heifer and the burning process, and that the verse in the Torah is referring to an unrelated form of impurity which does not invalidate him from the Red heifer ritual!
If one delves into this claim of the Pharisees, one will layer by layer uncover the falsehood of their methods, and the cynical and sinister nature of their political goals.
1) The Torah is very clear and explicit in what it says. The verse is giving a sequential prescription for the process of the Red heifer and the multi-stage purification process. It states explicitly that the bathing does not cause ritual purity on its own, and in fact it is the sunset which brings to an end that impurity.
2) To claim – as the Pharisees do – that the sunset is not part of the process , is a vile and cynical attack on the torah itself, rendering it illogical and rendering the verse a non-sequitur. How exactly can they derive anything from the verse if it is not logical?
3) Instead, they claim that there was all along an unwritten rule book which gave the true meaning of the verses in the Torah, even when the clear and obvious meaning goes against their beliefs.
4) The intention of the Pharisees was never to really comply with the Torah, it was to undermine the true heirs of Moses and Aaron, the Kohanim, who also had the Temple to tend to. Their intention was a coup, to take over from the Priestly sadducees, and to own both the Temple and the wealth of Israel. Their destruction of Temple purity resulted in the physical destruction of the temple. In this aspect, they only had short term success followed by long term misery and exile of the remaining Jewish people.
However, their long term success was in writing a new religion, a surrogate “Judaism” which undermines the Torah and its teachings, and purports to be the “authentic” form of Judaism to the undiscerning.