RESUMO
Objective To analyze the 2496 biological samples collected from 1574 larceny cases and improve the application of DNA in the larceny cases. Methods Make a summary of the biological samples collection methods and DNA test results in different type of larceny cases. Results Touch samples have already become the most common type of biological samples in larceny cases, but their DNA test success rate are still low, more work should be done for the DNA mixed type to improve DNA hit. The DNA positive result rate had statistical difference in biological samples with different collection methods. For the Touch samples, flocked swab and original are the best collection methods. Conclusion More Valuable biological samples collected by the crime scene investigators are the Key factor in improvement of DNA detection capability, awareness of trace biological evidence and the touch sample collection technique are very important for the crime scene investigators.