Biggie wasn't sacrificed. The way he was living, he knew he would die soon. That's why he named his albums the way he did and rapped about dying soon.
He had killed someone on DC and people were likely out for revenge. Also based on his autopsy, he was ~400lbs with an enlarged liver (hepatomegaly, probably fatty liver), enlarged heart (cardiomegaly) and enlarged thyroid with significant evidence of cardiovascular disease (streaking in vessel walls of abdominal aorta, etc.) at only 24 years old. He knew he was at death's door.