According to Jain scriptures and traditional Jain kathā:

• In Jainism, Krishna is regarded as a Vāsudeva, one of the 63 Śalākā Puruṣas (illustrious great souls), not as a Tirthankara or God.
• Jain universal‑history texts (like Trishashthi Shalaka Purusha Charitra type granths) describe that because Krishna took part in a lot of hiṁsā (violence) – battles, killings connected with the Mahābhārata war, etc. – he accumulated pāpa karma.
• As a result, after his death he is reborn in Naraka (a hell realm) to suffer the fruits of those violent karmas.

Very important points in Jain view:

• This hell-birth is not eternal.

After finishing the result of those karmas, the soul will again move on to other births and can eventually progress toward moksha.

• Different Jain traditions (Digambar and Śvetāmbara) may differ in narrative details (which hell, exact story sequence), but the basic idea is the same:

Krishna’s soul is currently in a hellish gati due to past violence, not in a state of liberation.

• Jain dharma does not worship Krishna; the path is centered on the 24 Tirthankaras and on stopping new karma and shedding old karma through right faith, right knowledge and right conduct.

You can read more in a simple Q&A style explanation here: