A disturbing letter targeting a teen with autism has shaken the boy's family and rallied the local community to their defense.The anonymous note was sent to 13-year-old Max's grandmother's house in Newcastle, Ontario, on Friday. Signed, "One pissed off mother," the letter refers to Max as a neighborhood "nuisance," "retarded" and a "dreadful" noise polluter. A photo of the letter was tweeted over the weekend by YouTube stars Lennon and Maisy, who identify themselves as family friends."Personally, they should take whatever non retarded [sic] body parts he possesses and donate it to science. What the hell else good is he to anyone!!!" the letter reads. "Do the right thing and move or euthanize him!! Either way we are ALL better off!!!"In an interview with Toronto-based station CityNews, Max's mother, Karla Begley, could not keep from crying as she read the section of the letter that suggests she euthanize her son."The more you go on, the worse it gets," Begley told CityNews. "Who says that about a child?"Worried for their safety, the family told CityNews that the police have been contacted, and they would like to press charges if possible. In the meantime, however, the neighborhood has rallied around Max, making a special effort to make him feel welcome in the community, CityNews reported.On Monday, Yahoo Canada News reported that police are investigating the letter. Spokeswoman Jodi MacLean told the news outlet that law enforcement is taking the threat "seriously."The original Twitter posting about the note had been retweeted over 3,600 times as of Monday afternoon, with people calling the letter "a shame," "evil" and "hateful."