Tyrann Mathieu Targeted In $5 Mil Extortion Plot, Officials Say

NFL star Tyrann Mathieu was threatened by a relative -- "I want 1.5 million by Friday or I am going to kill all you all" -- this according to federal court documents.

Officials claim 21-year-old Geourvon Keinell Sears tried to shake down the Kansas City Chiefs safety in April by threatening to contact TMZ with fake allegations of sexual misconduct if Tyrann didn't come up with the money.

For the record, we were never contacted by Sears.

At first, Sears' demand was $1.5 million -- but he later raised the number to $5 million, according to the documents filed in U.S. District Court in Louisiana.

Officials say Sears contacted Mathieu by phone calls and also text messages. Mathieu's family members feared for their safety, according to the court docs.

Sears was arrested on an extortion charge but was later released on $25,000 bond. He's due back in court next month. If convicted, he faces up to 20 years in prison.

Tyrann has reportedly made more than $31 mil in his NFL career and recently inked a 3-year, $42 million contract.

We spoke with Tyrann's rep, Denise White, who described the matter as a "very private and personal family issue."