Juvenile courts have exclusive initial subject-matter jurisdiction over any case involving a person alleged to be delinquent for having committed, when younger than eighteen years of age, an act which would constitute a felony *545if committed by an adult. R.C. 2151.23; 2151.26; State v. Wilson (1995), 73 Ohio St.3d 40, 43, 652 N.E.2d 196, 199. Before such an individual may be tried as an adult in common pleas court, the juvenile court must comply with the provisions of R.C. 2151.26 pursuant to procedures established by Juv.R. 30.
On August 30, 1994, when Golphin allegedly shot Clinton Butler, R.C. 2151.26 provided:
“(A)(1) * * * [A]fter a complaint has been filed alleging that a child is a delinquent child for committing an act that would constitute a felony if committed by an adult, the court at a hearing may transfer the case for criminal prosecution to the appropriate court having jurisdiction of the offense, after making the following determinations:
“ * * *
“(c) After an investigation, including a mental and physical examination of the child made by a public or private agency or a person qualified to make the examination, and after consideration of all relevant information and factors, * * * that there are reasonable grounds to believe that:
“(i) He is not amenable to care or rehabilitation * * * in any facility designed for * * * delinquent children;
“(ii) The safety of the community' may require that he be placed under legal restraint * * (Emphasis added.) 144 Ohio Laws, Part II, 2745-2746.
This statute, in effect both at the time of the shooting and at the time of Golphin’s amenability hearing, thus clearly mandated that a juvenile be given a physical examination by a qualified person prior to relinquishment of juvenile court jurisdiction.
Similarly, Juv. R. 30(B) provided at the relevant times:
“If the court finds probable cause, it shall continue the proceedings for full investigation. The investigation shall include a mental and physical examination of the child by a public or private agency or by a person qualified to make the examination.” (Emphasis added.)
The procedure used by the trial court here violated an express act required by a statute adopted by the General Assembly and a rule adopted by the Supreme Court.
Moreover, Juv.R. 30(F) provided, “In determining whether the child is amenable to the treatment or rehabilitative processes available to the juvenile court, the court shall consider the following relevant circumstances: * * * (1) The child’s age and mental and physical condition * * (Emphasis added.)
We have repeatedly recognized that use of the term “shall” in a statute or rule connotes the imposition of a mandatory obligation unless other language is *546included that evidences a clear and unequivocal intent to the contrary. See, e.g., Dorrian v. Scioto Conservancy Dist. (1971), 27 Ohio St.2d 102, 56 O.O.2d 58, 271 N.E.2d 834, paragraph one of the syllabus; State v. Pless (1996), 74 Ohio St.3d 333, 658 N.E.2d 766 (criminal statute); Lakewood v. Papadelis (1987), 32 Ohio St.3d 1, 4, 511 N.E.2d 1138, 1140-1141 (criminal rule). We have previously held that a statute or rule which uses the word “shall” in describing an act which is to be performed is not generally susceptible of a “substantial compliance” standard of interpretation. See State v. Pless at 340, 658 N.E.2d at 770.
The state emphasizes the considerable discretion vested in a juvenile court when determining whether to relinquish its jurisdiction over a juvenile to the court of common pleas, and cites State v. Watson (1989), 47 Ohio St.3d 93, 547 N.E.2d 1181, in support. However, Watson does not stand for the proposition that a juvenile court has discretion to omit from the record that which is expressly required by statute to be included.
R.C. 2151.26 requires that an investigation be conducted before bindover, and, in 1994 and 1995, the statute expressly required that the background investigation include both a mental and physical examination. It follows that the court’s bindover order in the case at bar was, at best, premature. The record fails to show the completion of the full investigation required to be conducted by statute before the court was authorized to make the critical determinations of whether Golphin was amenable to rehabilitation within the juvenile system and whether the safety of the community required that he be placed under legal restraint. See, also, State v. Douglas (1985), 20 Ohio St.3d 34, 36, 20 OBR 282, 284, 485 N.E.2d 711, 712 (“[A]s long as sufficient, credible evidence pertaining to each factor [enumerated in Juv.R. 30(E) ] exists in the record before the court, the bind-over order should not be reversed in the absence of an abuse of discretion.” [Emphasis added.])
Moreover, this court held unanimously in Gaskins v. Shiplevy (1995), 74 Ohio St.3d 149, 656 N.E.2d 1282, that a juvenile who alleged that he had been given no mental and physical examination prior to relinquishment of jurisdiction by a juvenile court stated a claim which, if true, demonstrated that the common pleas court that convicted him of a crime lacked jurisdiction over him. We discern no convincing reason to depart from this existing precedent in resolving the cause before us.
We acknowledge that the General Assembly amended R.C. 2151.26, effective January 1, 1996, to eliminate the requirement that a juvenile be given a physical examination prior to relinquishment of juvenile court jurisdiction. See R.C. 2151.26(C)(1)(c) (146 Ohio Laws, Part 1, 19-20). Similarly, in July 1997, Juv.R. 30 was amended to accord with the new statute by deleting all references to physical examination of juveniles. Nevertheless, the amendments to the controlling *547statute and rule were made subsequent to the proceedings at issue, and may not be applied retroactively.
The court of appeals did not err in concluding that the juvenile court failed to accomplish a legal transfer of its jurisdiction in that there is no evidence in the record that a physical examination of Golphin was performed as required by R.C. 2151.26 and Juv.R. 30. The court correctly recognized that the prosecution of Golphin in common pleas court was void ab initio. See State v. Wilson. It correctly reversed and remanded the cause to the common pleas court with instructions that the judgment of conviction against defendant be vacated. Upon implementation of that mandate, the cause must then be further remanded to the juvenile court for adjudication of the matters raised in the delinquency complaint, including possible resumption of bindover procedures.
Accordingly, the judgment of the court of appeals is affirmed.
Judgment affirmed.
F.E. Sweeney, Pfeifer and Cook, JJ., concur. Douglas, Resnick and Lundberg Stratton, JJ., concur in part and dissent in part.