The judge who reduced Karmelo Anthony‘s bond this week is getting some added security, TMZ Sports has learned, after law enforcement said she’s been the recipient of threats following her key decision in the murder case.

The Collin County Sheriff’s Office told us Tuesday it’s beefed up protection around Judge Angela Tucker in the wake of her Monday choice to lower the alleged H.S. track meet killer’s bail from $1 million to $250,000.

The CCSO said “court staff and concerned citizens” reported the menacing remarks made against the official … and now, its team of investigators, as well as the FBI are probing the matter.

“If the individual responsible is identified,” the CCSO said, “potential charges could include Unlawful Disclosure of a Residence Address or Telephone Number and Obstruction or Retaliation.”

It’s unclear exactly what the contents of the comments made against Tucker were … but the judge reportedly turned her X page private shortly after Monday’s hearing, presumably due to them.

An attorney for Anthony — the 17-year-old who’s facing one count of first-degree felony murder after he allegedly stabbed Austin Metcalf during a dispute over a seat on April 2 — had argued to Tucker a $1 million bond was unnecessary … due his client’s lack of criminal activity history.

However, prosecutors asked for it to remain in place, calling it the standard for murder cases in Collin County.

After lowering it, Tucker ordered Anthony to wear an ankle monitor and be confined to his home.