I enjoyed the slow burn on this one, and its dedication to a dynamic narrative. I particularly like the confirmation of anomalous status early in the description, as well as the minor format screw at the end. It was also nice to see a "last note" that wasn't a pat explanation for the entirety of the skip and a format screw that wasn't empty showboating. It was format alteration serving and extending the mystery of the narrative at its close rather than just resolving it in a few hasty lines.
I did feel that some editing could be done. For instance, this section:
Examination of materials recovered after the detainment of Mr. Everett confirmed this relationship. While the mechanism by which SCP-2888 occurs remains unknown, research at the time, combined with witness statements and other collected evidence, indicated that Mr. Everett at least partially influenced the commencement of 38 births of specimens genetically identical to Ms. Reckart.
Seems awkwardly constructed and worded to me. It could be simplified:
Materials recovered following Mr. Everett's detention confirmed this relationship. While the mechanism by which SCP-2888 occurs remains unknown, all research indicates Mr. Everatt at least partially influenced 38 successful live births of specimens genetically identical to Ms. Reckart.
This is, of course, merely a suggestion, but it is emblematic of the minor editing I think could be done throughout the work to make it even more effective.
I also balked slightly at the intake documentation. We establish through the description that this individual is intelligent and apparently believes in feigning madness as a reliable legal defense. Much of his preparation for his "work" is done to evade (successfully) legal authority. While this is interesting, (he does not recognize he is in thoroughly extralegal territory), the psych intake largely seems to be sand from which we are to sift the one moment of honesty regarding Everett's monstrous justifications. The extensive documentation explaining that he is attempting to avoid culpability and that he is a nonstandard killer is not necessary, in my opinion—these points are made clear through the description and from the monomaniacal and anomalous nature of the crime.
With regard to the "how he did it" angle? I for one am not unsettled by a lack of explanation. How is irrelevant. How is a MacGuffin. Madness like Everett's found a way to be sated. That's all we need know on the topic, in my opinion.
+1