By Kanishka Singh

WASHINGTON (Reuters) -The death of a Black college student whose body was found hanging from a tree on a university campus in Mississippi this week was ruled a suicide after an autopsy, police said in a statement on Thursday.

Demartravion "Trey" Reed, 21, was found dead early on Monday near the pickleball courts on Delta State University's campus in Cleveland, Mississippi, according to officials.

Civil rights advocates had called for a thorough and transparent investigation into the death while noting Mississippi's history of lynching and racially motivated violence in the 19th and 20th centuries.

Authorities and investigators had previously said there was no evidence of foul play. The local coroner's office said earlier this week there was no evidence to suggest Reed was physically attacked or assaulted before his death.

The Mississippi State Medical Examiner's Office conducted an autopsy on Wednesday whose "findings were consistent with the initial investigation, determining the cause of death to be hanging and the manner of death as suicide," the Cleveland Police Department said on Thursday, adding toxicology test results were pending and may take weeks.

Mississippi Democratic U.S. Representative Bennie Thompson earlier called for a federal probe into Reed's death.

All files and investigative material were turned over to the FBI and the U.S. Attorney's Office for review, the Cleveland Police Department said, adding they were in contact with federal officials during the probe.

Renowned civil rights attorney Ben Crump was retained by Reed's family. Crump said on Tuesday the family "cannot accept vague conclusions."

The university had said multiple law enforcement agencies were assisting in the probe. The FBI said on Wednesday it was prepared to investigate, "if, during the course of the local investigation, information comes to light of a potential federal violation."

Delta State University's enrollment last year stood at over 2,600 students, more than 40% of whom were Black.

(Reporting by Kanishka Singh in Washington; editing by Kat Stafford and Lincoln Feast.)