In this study we report the ultrasensitive detection of human semen/sperm cells enabled via a surface plasmon coupled emission (SPCE) platform that is of immense benefit from the forensic and criminology standpoint. The studies make use of the acid-fast property of sperm cells that endow the cells with the ability to retain fluorescent stains or dyes even upon acid-alcohol treatment, allowing their distinction and detection from other non-acid-fast cells that do not exhibit this property. SPCE studies on acid-fast stained semen and control samples were performed on the high-performance Ag-C60 substrates. On excitation with the 532 nm laser source, the SPCE signals arising from the semen and controls coated GLAG-C60 substrates were recorded. In this regard, we were able to detect approximately 10 sperm cells/mm2; which highlights the ultra sensitivity of the Ag-C60 SPCE sensing platforms. While the acid-fast nature of sperm cells ensures specificity, SPCE assures sensitivity. We demonstrated the application of these substrates as onsite forensic sensors; enabling the rapid, specific, and ultrasensitive detection of acid-fast sperm cells or semen samples in an unambiguous manner. This is of immense relevance to forensic investigation and analysis of sexual assault cases. The positive identification of semen samples can enable forensics to perform DNA analyses. The detection of semen can also facilitate doctors to analyze the samples for suitable treatment modalities to be administered.