Kurak
Kurak was a warp field specialist from Qo'noS, the Klingon homeworld. While she was a brilliant expert in the field of subspace morphology, her efforts went unappreciated by the Klingons. As such, she developed a hostile and defensive attitude when working with other scientists.
Kurak was present aboard the USS Enterprise-D in 2369 to witness the testing of Dr. Reyga's metaphasic shielding. The shielding worked, although it was initially sabotaged. Kurak nearly had a physical altercation with Reyga after the first failure of the technology, and made a threat against his life. Dr. Beverly Crusher suspected Kurak may have been the saboteur and that she later murdered Reyga to pursue the technology for herself, but she was cleared when Dr. Jo'Bril was revealed to be responsible. (TNG: "Suspicions")