Beyonce Receives Threatening Letters, Ups Security Over Longtime Stalker

Beyonce's team has been briefed and will be watching for a long-time stalker during her promotional tour and an upcoming show in London this week.

According to The Sun, Bassey Essien, a South West London resident, has already been warned to stay away from Beyonce thanks to a 2011 anti-harassment order, but sources say he's still sending her letters and they've become more "threatening."

"Staff have been told to watch out for obsessed fan Bassey Essien when the Crazy In Love singer headlines the Sound Of Change concert on Saturday. It is believed she has been sent sick threatening letters," The Sun reports.

Essien has been sending letters to Beyonce for at least four years. One was extremely bizarre, claiming that Beyonce was an impostor who killed "the real Beyonce."

“Staff have been briefed on the situation and pictures of him have been passed round. They’ve been told to keep their eyes open and be extra vigilant," a source close to Beyonce told The Sun. "Security has been increased on a few engagements now, especially for her UK promo."

Beyonce is due to play the Sound of Change concert Saturday, which was organized to support education, health and other causes for women. Jennifer Lopez and Rita Ora are also slated to perform.