Did Metallica steal the 'Enter Sandman' riff from exodus?

There is a longstanding debate about the similarities between Metallica's "Enter Sandman" and Exodus's song "Impaler." While both riffs share a similar feel, Metallica's James Hetfield has acknowledged Exodus's influence on the thrash metal scene. However, there has been no definitive evidence to suggest that Metallica intentionally stole the riff; rather, it may be a case of mutual influences within the genre. Ultimately, the similarities could stem from common musical influences rather than direct theft.