Redskins linebacker Perry Riley pursued the ballcarrier until he heard a whistle. At that point he slowed down. The ballcarrier did not, running the next 17 yards into the end zone.

After the game, the officials admitted they blew the whistle but not the play in the Redskins' 21-13 loss to the Panthers at FedEx Field on Sunday. Referee Carl Cheffers told a pool reporter after the game that they let DeAngelo Williams' 30-yard touchdown run stand because, Cheffers said, "We just felt when the whistle blew, the player would have already scored a touchdown. ... By the time the whistle blew, he had already crossed the goal line."

Replays showed, however, that Williams was around the 17-yard line when the whistle blew. Riley was coming at an angle. It's debatable whether Riley would have stopped Williams, but it would have been close.

"I could have pushed him out," Riley said. "He didn't need much to be pushed out of bounds. He was still trying to tiptoe the sideline, and I pulled off, and that's when he caught his balance and started running. I'm going to the refs like, 'You all blew it dead,' and they tell me, 'Who blew it dead.' 'I don't know which one of you all blew it dead. I heard a whistle.'?"

Redskins coach Mike Shanahan said the officials told him they were trying to decide whether a Panthers receiver had held cornerback DeAngelo Hall on the play.

"I didn't know about the whistle," Shanahan said.

The touchdown gave Carolina a 7-3 lead. But it was the Redskins' 13 penalties that really did them in against the Panthers. Penalties hurt them throughout the game, including a scoring drive late in the game. Two scores were nullified by penalties. Washington eventually scored, but it cost the Redskins 29 seconds plus a stoppage at the two-minute warning.

"You can't overcome all those penalties," Redskins left tackle Trent Williams said. "They're just as bad as turnovers."

Said Redskins left guard Kory Lichtensteiger: "Every game we've lost, we just find a way to shoot ourselves in the foot."