Las Vegas Raiders coach Jon Gruden said several of his players made a mistake when they didn’t wear masks or practice social distancing during a charity event that violated league and local COVID-19 rules.

About 10 players attended the fundraising event held Monday night by teammate Darren Waller’s foundation to raise money intended to help young people overcome drug and alcohol addiction.

Players were seen on video without masks during the indoor event while talking and mingling with guests, who also weren’t wearing masks.

“We’ve done a good job, done an excellent job,” Gruden said Wednesday. “Last night, it was addressed with our players. They walked in with their masks on. Sometimes you go to a restaurant and take your mask off. They’re aware of their mistake. But we’ve done an excellent job of using our manners, taking proper care of each other.”

This is the latest possible infraction of the COVID-19 protocols by the Raiders early this season. A person familiar with the punishments said Gruden was fined $100,000 and the team fined $250,000 because he failed to wear his mask properly on the sideline during a Week 2 game against the New Orleans Saints. The person spoke on condition of anonymity because the league hadn’t made any announcement.

The team is also being investigated for allowing an unauthorized team employee into the locker room after the Saints game.