Is a male who intentionally kills another male at the age of fifteen subject to qisas, or is he considered not yet an adult?

The age of puberty is the completion of fifteen lunar (Hijri) years for a male who has not shown other signs of puberty such as nocturnal emission or growth of pubic hair. If the killer has reached this age, he is considered an adult and legally responsible, and the penalty of Qisas (retribution in kind) is applied to him for intentional killing, unless the victim's heirs pardon him. However, if he has not reached this age, he is considered a minor and not legally responsible. His killing is then considered an accidental killing, and a mitigated Diyya (blood money) is obligatory upon his Aqila (male relatives responsible for paying blood money) payable in installments over three years.