Jim Harbaugh expressed frustration with the referees following the San Francisco 49ers' 34-31 loss to the Baltimore Ravens.

"No question in my mind there was a pass interference and a hold on Michael Crabtree on that last one," Harbaugh said about Colin Kaepernick's pass attempt to Crabtree on 4th and goal from the five-yard line.

Harbaugh also thought a pass interference call on Chris Culliver that extended a Ravens' eventual scoring drive was called incorrectly.