Burden of proof refers to the amount of evidence or proof required to adequately prove disputed facts in a court of law, and which party has the obligation to prove the disputed facts in order to prevail in court. In criminal prosecutions (cases) the government or prosecution has the burden to prove the accused defendant’s guilt beyond a reasonable doubt. This has been the standard for criminal prosecutions in the United States since at least 1880 when it was first mentioned by the U.S. Supreme Court. The determination of whether there is reasonable doubt as to an accused defendant’s guilt may be characterized by the question of whether there is an alternative explanation of the facts that seems plausible to the jurors.

In Connecticut, as in all states across the United States, the burden of proof in criminal prosecutions lies with the government or prosecution. This means that the prosecution must prove the defendant's guilt 'beyond a reasonable doubt.' This is the highest standard of proof required in the American legal system and has been a cornerstone of criminal law since it was established by the U.S. Supreme Court in the late 19th century. The concept of 'reasonable doubt' is subjective and ultimately depends on the jurors' interpretation. Jurors must consider whether there is a plausible alternative explanation to the facts presented by the prosecution that could lead to a doubt regarding the defendant's guilt. If such doubt exists, the jury is instructed to acquit the defendant. This standard is designed to protect the accused by ensuring that no one is convicted based on insufficient or ambiguous evidence.