A fan who attended the Chiefs’ game last Thursday at Arrowhead Stadium has tested positive for COVID-19 the following day, Kansas City Health officials report. The Chiefs said they were able to pinpoint the names of other members in the party, plus detailed information about the path and location of entry.

The Kansas City Health Department has notified ten fans to quarantine after possibly being exposed.

There may have been a breakdown in the testing process at Arrowhead Stadium. A Chiefs spokesperson said the fan was not tested and said they do not yet know how the fan was able to bypass pregame testing.

The Chiefs and Jacksonville Jaguars were the only teams that allowed fans during the first week. Cleveland allowed fans on Thursday night and Miami and Indianapolis plan to follow suit.