Actually, Torah Jewish Law is different than the various legal systems of modern Western countries.
The Talmudic Sages made many comments and elaborations on adjudication for serious crimes such as murder.
Among them: They declared that the commonly spoken Biblical admonition of "An Eye for an Eye and a Tooth for a Tooth", which is an inaccurate translation from the Hebrew original which states "For an Eye...Eye"..."For a Tooth...Tooth" must be considered a demand for monetary and/or other compensation to one suffering from the intentional or unintentional harming of another's person or property...so that should someone blind another, they must pay and compensate to an amount which a court would consider adequate to repay such a disabling injury, etc...
For the crime of murder: The Sages declare that Torah demands an eyewitness to the actual event must accuse the perpetrator in court. For example, if some passerby heard screams from a house, and from the house ran a man holding a bloody knife, then the one fleeing the scene may not be charged with murder, because no eyewitness saw the actual murder...they only saw someone fleeing on foot, who may or may not have committed any crime...they might have been the first to encounter a murder victim, and in panic picked up the murder weapon and run hysterically to get help, etc...merely "circumstantial evidence" can not incriminate for taking another's life in Jewish Law.
In addition, should a person be charged with murder and convicted by the testimony of eyewitness, the eyewitness must not only witness the murderer be stoned to death, but must cast the first stone at the condemned! This law was to prevent frivolous charges...making such a condemnation so heinous that the accuser must be personally willing to execute the condemned.