Who's fault was it?

Yesterday (Sunday) during the Advance Auto Parts Clash in Daytona Jimmie Johnson got into Paul Menard and they wound up taking out most of the field...who was at fault? Did Paul drop down on Jimmie? Was JJ trying to side draft? (I blame both of them...gotta give 'em more space)

'Big One' takes out leader Menard, plenty of others

Contact between Jimmie Johnson and Paul Menard touches off the "Big One" during the Advance Auto Parts Clash at Daytona International Speedway. Johnson would take the lead and win the race.