Here the printer’s manuscript has the redundant “their crime which they had done”, while the 1830 edition has the more acceptable “the crime which they had done”. Nonetheless, there are at least five passages in the Book of Mormon where the original text had a similar kind of redundant relative clause; in each of these passages, the possessive pronoun before the head noun could be replaced by the, thus making an easier reading:
In the Alma 55:21 passage, the 1830 compositor changed the his to the. This change provides direct support for the hypothesis that here in 3 Nephi 6:26 the 1830 compositor could have made the same change from the redundant “their crime which they had done” to the expected phraseology, “the crime which they had done”.
The 1830 reading is, of course, what we expect in 3 Nephi 6:26. And usage elsewhere in the original (and current) text supports the definite article the in similar phrases referring to a crime that has been committed:
Consistent with these examples, one could argue that here in 3 Nephi 6:26 the original manuscript read “the crime which they had done” (the 1830 reading). Or contrarily, one could argue that this systematic usage elsewhere in the text led the 1830 compositor to make the change from an original but unexpected “their crime which they had done” to the expected “the crime which they had done”.
When we consider the cases where Oliver Cowdery permanently changed an original the to their and contrast them with the cases where the 1830 compositor changed an original their to the, we find a nearly equal amount of evidence for both types of change. Oliver permanently changed the to their in three cases, although in each instance there was a nearby their that seems to have prompted the change:
In the second example, the original text apparently read “and the privileges of their church” (see the discussion under 3 Nephi 2:12). Here in 3 Nephi 6:26 there is no following their, so there is no direct motivation to change an original the to their. But one could argue that the following they in “which they had done” could have prompted the change.
Here are two instances where the 1830 compositor set the in place of a correct their:
Overall, either variant in 3 Nephi 6:26 is possible from the viewpoint of textual transmission. But because the 1830 compositor made the specific change from his to the in Alma 55:21, we have direct evidence that the compositor could have made the specific change from their to the here in 3 Nephi 6:26. The critical text will therefore restore the difficult reading here, the redundant “to be judged of their crime which they had done”. Usage elsewhere in the text supports this kind of redundancy, although not in this particular expression.
Summary: Restore the difficult but possible reading in 3 Nephi 6:26 with its use of their rather than the expected the: “to be judged of their crime which they had done”; there is considerable evidence for such redundancy in the original (and current) text.