Yes, Darren Seals was most likely murdered. He was an activist who had strong opinions that opposed the opinions of others. There is a strong chance that someone who did not agree with his opinions decided to stop his activist activities by ending his life. Having him burn in a car could make it seem like an accident, while also destroying evidence of foul play.
Darren Seals was not only found in a burning car, but he had been shot and killed prior to being put in the car.This is absolutely evidence of a murder and it is pretty clear that someone tried to cover it up, although it seems like they were not as successful.
Darren Seals was an activist in the violent city of St. Louis and it is possible that he made enemies during his public stance. The investigation will need to determine the facts of the death but the burning car was likely set on fire to destroy evidence. This appears to be a murder case.
No, we cannot say for sure that Darren Seals was murdered, since we do not have the evidence. However, it is possible. There should be a full investigation into his death immediately. That will be the only way to find answers and discover what really happened moments before his body was found.