10:42 AM PT -- A spokesperson for the Florida International University Police Dept. tells TMZ Sports ... cops responded to one of the campus' dorms on Wednesday after receiving a call about a medical emergency.
According to the spokesperson, "officers did work on" Knox when they arrived on the scene until fire rescue showed up. Knox was then transported to a nearby hospital -- but he later died there.
No further details were given.
9:10 AM PT -- According to the Miami-Dade Police Dept., foul play is not suspected. An official cause of death is still being determined by the medical examiner's office.
Tragic news ... Luke Knox, a Florida International University linebacker and brother of Bills star Dawson Knox, has died suddenly at the age of 22.
FIU officials and Buffalo head coach Sean McDermott just confirmed the passing ... though a cause of death was not revealed.
"Our hearts go out to Dawson and his family during this time," McDermott just told reporters at Bills training camp. "We're right there with him and supporting him and his family. Just tragic news that I woke up to this morning."
Luke initially began his college career at Ole Miss in 2018 -- playing both linebacker and tight end. He transferred to FIU this offseason -- and had been expected to compete for a starting LB spot this year.
FIU's head coach Mike MacIntyre, who coached Luke at both Ole Miss and FIU, said in a statement Wednesday he was heartbroken over the football player's death.
"Luke’s family is special to me and they will continually be in my heart and my prayers during this difficult time," MacIntyre said. "On behalf of the entire FIU football family, I extend sincere condolences to Luke's family and all who love him."
Dawson was very close with Luke -- the two played together for a season at Ole Miss in 2018 -- and the guys actually shared a very funny moment when Dawson was drafted by Buffalo in 2019.
Luke, celebrating the pick, accidentally punched Dawson in the face -- causing him to bleed on his big night.
"So dang proud of you bro," Luke said in a post to Dawson on the draft night. "Time to go get what's yours!! Love you"
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Dawson has yet to publicly comment on the tragedy.