The students who bullied bus monitor Karen Klein have reportedly received death threats from viewers of the bullying video, which went viral this week.

According to CBS News, the seventh grade boys in the video, Making The Bus Monitor Cry, and members of their families have all received death threats for bullying Klein, a 68-year-old bus monitor for Athena Middle School near Rochester, New York.

Having garnered more than four million views as of Friday, the world became aware of Klein's story of enduring harsh bullying from students after the video went viral on YouTube. The 10-minute clip shows Klein literally in tears as the students taunt and harass the 23-year bus monitor veteran. The video outraged many, prompting a $400,000 fundraiser called Let's Give Karen The Bus Monitor a Vacation.

The death threats came in spite of two students, and their parents, issuing apologies on Thursday.

One of the bully's father, Robert Helm, told Klein, There's no excuse. And we're going to get to the bottom of that, but it really broke my heart and I shed a lot of tears thinking about that whole thing and I just want you to know that my family, all of us, are deeply saddened by this whole thing and we're going to get it right.

Klein responded with concern for the family. But you'll be OK, right?, which CBS News said was an allusion to the death threats.

According to CBS, Klein is aware of the death threats the families of the bullies have received.

I didn't like that, she said.

Apologies from the students continued to pour in on Thursday on 360 Anderson Cooper, where two of the four bullies apologized to Klein.

I am so sorry for the way I treated you, a student named Josh said in a statement. When I saw the video I was disgusted and could not believe I did that.

I wish I had never done those things, another student, Wesley, said in a statement. If that had happened to someone in my family, like my mother or grandmother, I would be really mad at the people who did that to them.

Klein, however, does not buy the apologies, since they were not in person, especially Josh's.

Even if he wasn't picking on me, it was something else, Klein said on Anderson Cooper. So I just don't think I would believe anything Josh had to say.

But despite it all, Klein does not believe the students are inherently bad.

I want them to make sure that they never do this again, to anybody, she said. I would like them to be at least kept off the bus for a year, and be forbidden to play any sports.

So far, Karen Klein doesn't think she will press criminal charges on the students but Athena Middle School is conducting an investigation into the bullying incident captured on video, which you can view below.