[2] While the court ruled that the then-common practice[3] of submitting these reports without testimony was unconstitutional, it also held that so called "notice-and-demand" statutes are constitutional.

The informant stated that an employee repeatedly received phone calls at work, after which he would leave the store, get into a blue sedan, and return a few minutes later.

Police detained and searched the employee finding four clear plastic bags containing a white powder substance, alleged to be cocaine.

Melendez-Diaz was charged with distribution and drug trafficking of cocaine in an amount between 14 and 28 grams under the Massachusetts Controlled Substances Act,[5] a felony punishable by not less than three years imprisonment.

[6] Melendez-Diaz objected to their admission asserting that the Supreme Court decision in Crawford v. Washington required the forensic analyst to testify in person.

541 U. S. 36, 51–52 (emphasis added) The Court found that the forensic analyst who tested the contraband substance and reported that it was cocaine was a witness for purposes of the Confrontation Clause.

The Court noted that the Kirby decision was part of a long established rule that evidence that proves only one essential element of a crime is nevertheless accusatory for purposes of the Confrontation Clause.

The Court rejected the argument that the analyst was not a conventional witness because he or she recorded the immediate results of a chemical test rather than recalled a historical event.

The Court referred to the companion case to Davis v. Washington, where it ruled that statements to police immediately after an incident of domestic violence were "non-testimonial" and part of "an on-going emergency" and therefore admissible.

[10] The Court rejected the argument that the neutral and especially reliable nature of the forensic chemical testing would exclude it from the confrontation requirement.

It cited a study of forensic laboratories where analysts would falsely record results of tests never performed because of the high volume demands of law enforcement.

The court cited one particular study in which invalid forensic testimony contributed to a false conviction in 60% of the cases where defendants had achieved exoneration.

[12] The Court rejected Massachusetts' claim that the forensic affidavits met the business records exception to the hearsay rule.

Citing Crawford, the court stated that most business records will escape Sixth Amendment scrutiny not because they meet the exception to the hearsay rule, but because they are non-testimonial in nature.

The Court agreed with the scenario proposed by the petitioner: that the prosecution would present affidavits to the judge ex parte and wait for the defense to subpoena whom he chose.