A 13-year-old boy hanged himself this week in his Brooklyn home — and left behind a heartbreaking note asking his loved ones not to “let the school do an assembly about this,” according to cops and police sources.

The teen was discovered hanging from an unknown object inside the home on Coffey Street near Ferris Street in Red Hook around 7:20 p.m. Monday, cops said.

His death is being investigated as a suicide, police said.

According to sources, the boy left behind a note that said, “Goodbye I love you guys so much but life to [sic] hard, I don’t blame any of you guys. Don’t let the school do an assembly about this.”

He was taken to Methodist Hospital, where he was pronounced dead about a half-hour later, the sources said.