Ngakoue said on Twitter that a Bills player wearing No. 64 was "goin[g] to come harder than some weak racist slurs."
Ngakoue ended his tweet with the hashtag #Iaintjonathanmartin!
Great win to day! And 64, you goin have to come harder than some weak racist slurs. I'm proud of my African heritage, as are 70% of the other Black players in this league. #Iaintjonathanmartin!— YANNICK NGAKOUE! (@YannGetSacks91) January 8, 2018
Ngakoue could not be reached for comment. The Bills and Incognito's agent, David Dunn, did not immediately respond to a request for comment Sunday evening.
The NFL said it is "looking into" the accusations levied against Incognito.
Bills lineman Dion Dawkins tweeted in support of Incognito.
Just for the world to know, everyone always tryna put some bad thing on @68INCOGNITO i was next to my guy the entire game and the entire season and believe me, if he was saying some racist stuff I would have been the first to let him know that was out of line. Cut The BS— Dion Dawkins (@DDawkins66) January 8, 2018
Incognito, 34, has made the Pro Bowl each of his three seasons since signing with the Bills in 2015. Buffalo gave Incognito a second chance in the NFL after the Miami Dolphins suspended him for the final eight games of the 2013 season for his role in a bullying scandal in which ex-offensive lineman Jonathan Martin was a target.
NFL investigator Ted Wells released a report in 2014 detailing "a pattern of harassment" against Martin by Incognito and other Dolphins players that included racial slurs. Incognito's attorney later called the report "replete with errors."
The NFL cleared Incognito later in 2014 to return to football, but he spent that season out of the league before joining Buffalo the next year.
ESPN's Mike Rodak contributed to this report.