Rasen no Meikyuu: Idenshi Sousa

In Tokyo, a murderer leaves his signature, an "X" on the dead body. When found, the mark appears eerily similar to that of the one seen on the body of the dead wife of Detective Genji Andou. Banned from the investigation, he secretly reaches out to Jin Jinbo, an associate professor at the medical school's genome analysis lab. Who better than a DNA expert to identify this potential serial killer? (Source: MyDramaList)