Complex sentence: Having no memory of the procedure, The Doctor attempts to reconstruct evidence surrounding the time period, and a perusal of deliberately deleted files in his extensive photographic collection of the crew reveals pictures of a crewmember of whom he has no recollection-Ensign Jetal.
Split into simpler sentences: Having no memory of the procedure, The Doctor attempts to reconstruct evidence surrounding the time period, but finds that some the files in his extensive photographic collection of the crew have been deleted. A reconstruction and search of the files reveals pictures of a crewmember of whom he has no recollection-Ensign Jetal.