Why do Ahmadies claim that Musailma Kazzab was an apostate?

Islam

Ahmadiyya

Ahmadiyyat

MTA

International

Rahe

Huda

Rah-e-Huda

Rahehuda

Hadhrat

Mirza

Ghulam

Ahmad

Qadiani

Qadian

Promised

Messiah

Holy

Prophet

Muhammad

Mohammad

Ahmadi

Muslim

Isa

Ibne

Maryam

Ibn-e-Maryam

Persecution

Bait-ul-Futuh

Bauitul

Futuh

Khalifa

Khalif

Caliph

Love

for

All

Hatred

None

Asif

Mahmood

Basit