Fundamental biological molecules such as amino acids and sugars have been discovered in meteorites, but none of these species have yet been definitively detected in the interstellar medium (ISM). While both the number of detected interstellar molecules and their chemical complexity continue to increase, understanding of the processes leading to their formation is lacking. Recent chemical models suggest that organic radicals formed during the photolysis of interstellar ices provide the building blocks for the larger organic molecules found in star-forming regions.  In order to investigate these interstellar prebiotic chemical pathways, we are developing a terahertz (THz) cavity ringdown spectrometer to study the unstable, reactive molecules that are key reaction intermediates.   In this talk, I will present the initial results of the instrument development and spectroscopic studies.  I will also outline our future plans for this instrument and the link to our ongoing projects in observational astronomy and astrochemical modeling.