Karmelo Anthony Case

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.

2:23 PM PT -- Just hours after a judge in Texas agreed to drastically reduce Karmelo Anthony's bond amount, the 17-year-old is out of the local county jail.

A local reporter, Steven Dial of FOX 4 Dallas, captured the moment Anthony walked out of the facility ... where he's been since April 2.

Karmelo Anthony -- the teenager charged with the murder of 17-year-old Austin Metcalf -- had his bond drastically reduced during a court hearing Monday morning ... from $1,000,000 to $250,000.

Mike Howard, Anthony's new attorney, argued the $1 million bond was unnecessary ... as his client has no history of criminal activity.

"Give this young man a chance to get out of jail and be with his family," Howard said.

Thousands of dollars have been raised for Karmelo Anthony -- the 17-year-old accused of stabbing and killing a fellow teenager at a track meet last week -- as his family continues to defend him.

A GiveSendGo set up by the boy's close relatives has garnered, as of Monday morning, $155,848 ... after Karmelo's father, Andrew, stated last week Karmelo was "not the aggressor" in the April 2 tragedy that resulted in the death of Austin Metcalf.

The Anthonys stated in the fundraiser their goal was to get $200,000 to help defend Karmelo ... as they believe the "the narrative being spread" about the boy "is false, unjust, and harmful."

The 17-year-old accused of stabbing and killing another student this week at a high school track meet was provoked ... according to his father.

Andrew Anthony -- the dad of teenage murder suspect Karmelo Anthony -- told the New York Post on Thursday that Austin Metcalf and his friends were the ones who started Wednesday's altercation in Frisco, Texas that ended in tragedy.

"He was not the aggressor," Anthony insisted. "He was not the one who started it."

The brother of the 17-year-old high school athlete who was stabbed to death at a track meet on Wednesday said the tragic incident was all sparked by an argument over a seat.

Hunter Metcalf told WFAA his twin brother, Austin Metcalf, got into a tiff with Karmelo Anthony while out at the event in Texas ... because the Frisco Centennial High School 17-year-old was sitting underneath their Frisco Memorial High School tent.

"We asked him to move," Hunter said. "He started getting aggressive and talking reckless."

A 17-year-old has been charged with one count of murder ... after he allegedly stabbed another 17-year-old during an altercation at a high school track meet in Texas on Wednesday.

Frisco Police said the incident took place at around 10 AM at the Frisco Independent School District's Kuykendall Stadium ... where several students were competing in the University Interscholastic League's (UIL) District 11-5A championship.

According to cops, Frisco Centennial High School's Karmelo Anthony killed Frisco Memorial High School's Austin Metcalf following a dispute at the event.