Did Seneca Crane die in the first Hunger Games book?

Yes, Seneca Crane was executed at the end of the first Hunger Games book, *The Hunger Games*.

He was responsible for the rule change that allowed two victors from the same district to win, which ultimately led to Katniss and Peeta's victory. However, the Capitol was furious that he had allowed a double victory and as punishment, he was forced to drink a poisoned berry juice.