Praise be to Allah.
We put this question to Shaykh ‘Abd-Allaah ibn Jibreen, may Allaah preserve him, who answered as follows:
Leaving the blood in the animal after slaughter and not draining it is haraam and is not permitted. Allaah says (interpretation of the meaning):
“Forbidden to you (for food) are: Al-Maytah (dead animals – cattle-beast not slaughtered), blood…” [al-Maa’idah 5:3]
And Allaah knows best.