AceShowbiz - Beyonce Knowles was threatened during the filming of a documentary on the life of slain teenager Trayvon Martin.

The 17-year-old African-American was shot and killed by neighbourhood watch zealot George Zimmerman in 2012. He was charged with murder, but acquitted at trial after claiming self-defence, based on Florida's controversial stand-your-ground law.

Trayvon's death sparked outrage across the U.S., with former American President Barack Obama becoming emotional during a press conference when discussing the killing. "If I had a son, he’d look like Trayvon," he told reporters.

Jay-Z has been among the many high-profile names campaigning for justice for Trayvon, and the rap mogul is one of the executive producers of the Paramount Network docu-series about the tragedy, titled "Rest in Power: The Trayvon Martin Story".

During filming, Zimmerman is revealed to have threatened Beyonce and her husband in a series of text messages.

According to The Blast, the 34-year-old called the mother-of-three a "broke w**re".

"Oh yea, and tell Jay-Z he's a b**ch and his wife is a broke w**re. If I see either of them in my life, they'll find themselves inside a 13 foot gator (alligator)," Zimmerman wrote to private investigator Dennis Warren.

Zimmerman previously slammed the project and said he wanted to "beat Jay-Z" and "feed him to an alligator" after alleging TV executives had hounded his family for interviews.

"I know how to handle people who f**k with me, I have since February, 2012," he sneered, referencing the date of Trayvon's death.

Investigator Warren was hired to track down potential participants for the docu-series, and later found himself on the receiving end of hundreds of harassing messages and voicemails from Zimmerman.

Back in May, he was charged with stalking and harassing Warren.