STR (short tandem repeats) multiplex systems can produce reliable results to link a suspect to a crime with 1 nanogram or less of evidence. One of the first highly publicized court cases in Europe used the Gene Print TM CSF1PO, TPOX, THO1 Multiplex System (CTT) for the analysis of DNA Evidence in a serial killer case. Using STR multiplex amplification systems, typing specific regions of the ten genetic markers was possible while consuming only five nanograms of the sample DNA. The analysis of DNA polymorphism proved to be a very useful and reliable tool in helping to solve the case. Since this case, multiplexing of STRs has been accepted in many European court cases. STRs are also being used for the development of criminal databases in some European countries to link suspects to crime scenes and similar crimes to one another. Today, the amplification of STR loci using PCR (polymerase chain reaction) is the preferred method for typing biological evidence found at crime scenes.