Detection of seminal stains on items such as clothing and bedding is a significant element of investigation in sexual assault cases. The use of alternative light source may assist in their identification. The objective of the investigation was the evaluation of human semen visualization with the use of alternative light source for the purpose of genetic identification. The tests demonstrated that experimentally prepared semen stains on the bright base could be best seen in the natural light and white light when the semen was diluted at a ratio 1:10. The complete typeability of AmpFISTR SGM Plus kit loci was evaluated in semen which was diluted at a ratio 1:1750 and typeability of AmpFISTR SGM Plus kit loci was incomplete in semen diluted at a ratio 1:2000. After washing with laundry detergents, semen stains were still recognizable under ALS wavelength 455 nm, while wearing orange goggles.