I found a selectively mute child. But he is not a real person. He is a character in a Japanese video game.
His name is Marc Brown. He is a character of Policenauts, a Japanese adventure game released in 1994.
Policenauts (Wikipedia)
The word "mutism" appear on the official website of Policenauts.
I'm surprised to know that producers of the game knew such an unknown disorder.
But I think that the producers misunderstood about selective mutism. Traumatic incident don't usually cause selective mutism.
The director of Policenauts is Hideo Kojima, a famous game designer. He was listed on Newsweek magazine's "10 most influential people to shape the future" in 2001.
Although I played video game in my childhood, I don't know Policenauts. I played Nintendo Entertainment System in the '80s.
Index of SM in Japan