Matthew Mills believes that the Sandy Hook school massacre in the US didn't happen. Unfortunately he's taken his belief to an extreme, publicly harassing the sister of one of the victims, a school teacher called Victoria Soto. Victoria has been hailed as a hero for her efforts to protect the children under her care, and lost her life in the process. Matthew believes that Victoria never existed, and has been harassing her sister in an effort to get her to admit this.
Matthew was arrested for having signed up for a charity run in the name of Victoria Soto, and then using the opportunity to show a picture of Victoria to her sister, Jillian, asking if it was photoshopped.
This is not the first incident with Matthew Mills. Previously he has intruded on a TV interview at the SuperBowl, shouting into the mic:
"Investigate 9/11. 9/11 was perpetrated by people within our own government."