Divrey Hayamim Alef 10:13-14

So Sha'ul died for his ma'al (unfaithfulness) which he committed against HASHEM, even against the Devar HASHEM, over which he was not shomer, and also for consulting an ov (one with a familiar spirit) to seek guidance; And inquired not of HASHEM; therefore He slaughtered him, and turned over the kingdom unto Dovid Ben Yishai.