Angry fans have since lashed out at Williams with threats, while others are shocked that some of them could behave in such manner toward Williams.
@KyleWilliams_10. I hope you, youre wife, kids and family die, you deserve it, one user tweeted.
Kyle Williams better keep one eye open... Im gonna bust both that dudes kneecaps see if he ever plays in red and gold again, another fan wrote.
BAH!San Francisco 49er kick returner Kyle Williams attempted to shoot himself after today's game but he dropped his gun, another wrote.
I doubt I will ever forgive kyle williams #jackass, a Twitter user posted.
But there are others who weren't as harsh on Williams.
49ers fans giving Kyle Williams death threats are sick sick people, one man tweeted.
#49er fans want to blame Kyle Williams but there is no way of knowing if they would've won if he didn't fumble! one user wrote.
Death threats to Kyle Williams? Dont call urself a #49erFaithful if u dont knw what The Team. The Team. The Team. means. Live n die as one, another posted.
According to Yahoo Sports, Williams had returned only five punts in his NFL career, but was thrusted into the game on Sunday when the team's regular return man, Ted Ginn Jr., got sidelined with a knee injury. The Giants heads to the Super Bowl with a 20-17 victory over San Francisco in the NFC championship game.