Image copyright Courtesy MCIR and ProPublica Image caption Three Mississippi university students flank the sign honouring slain civil rights icon Emmett Till

Three US university students have been suspended from their fraternity after posing with guns in front of a memorial honouring a slain civil rights icon.

The photo, obtained by the Mississippi Center for Investigative Reporting and ProPublica, shows the three brandishing firearms by the bullet-ridden sign.

The memorial honours 14-year-old Emmett Till, whose torture and murder in 1955 galvanised the civil rights movement.

The three may now face an investigation by the Department of Justice.

"The photo is inappropriate, insensitive and unacceptable," said a representative of the Kappa Alpha fraternity's national order in a statement, adding that "it does not represent" the fraternity.

Image copyright Emmett Till Interpretive Center Image caption Memorial commission head Patrick Weems says the site is the subject of constant abuse

On its official website, Kappa Alpha Order calls Robert E Lee - a confederate general who fought against the US government during the Civil War - the group's "spiritual founder".

The fraternity's University of Mississippi chapter did not return a request for comment.

According to ProPublica and the Mississippi Center for Investigative Reporting, one of the students posted the photo to his private Instagram account in March 2018.

It shows the students in front of a plaque marking the spot where Till's body was recovered, part of a wider memorial effort by the Emmett Till Memorial Commission.

Ole Miss student Ben LeClere holds a shotgun, while his Kappa Alpha fraternity brother, John Lowe, squats below the sign for Till, the outlets reported. A third student stands with an AR-15 semi-automatic rifle.

Mr LeClere reportedly posted the picture on Mr Lowe's birthday, accompanied with the caption "one of Memphis's finest and the worst influence I've ever met".

According to the outlets, the photo received 274 likes before it was taken down.

Mr LeClere and Mr Lowe were not able to be reached for comment.

It is unclear if the sign - pocked with bullet holes in the photo - was damaged by the students themselves.

Though the students have been suspended from their fraternity - temporarily banning them from activities hosted by the social club - they have not yet been disciplined by their university.

A spokesman for the school, Rod Guajardo, told BBC News that the students' actions are "offensive and hurtful" but do "not violate the school's code of conduct".

"It occurred off campus and was not part of a university-affiliated event," he added.

"We stand ready to assist the fraternity with educational opportunities for those members and the chapter," Mr Guajardo said.

Image copyright Scott Olson/Getty Images Image caption A plaque marks the gravesite for Emmett Till at a cemetery in Illinois

Both the FBI and the Justice Department's Civil Rights Division have been alerted to the photo by the university for further investigation, the outlets report.

The Department of Justice declined to comment.

What happened to Emmett Till?

Till was brutally murdered in August 1955 after allegedly whistling at a white woman during a family visit to Mississippi. He was beaten so badly that his face was unrecognisable when the body was recovered from the Tallahatchie River three days after the attack.

His body was brought to Chicago, where thousands of people attended his open casket funeral. The brutality of the crime galvanised the civil rights movement.

Till would have turned 78 on Thursday.

The two white men known locally to have carried out the attack were acquitted by an all-white, all-male jury.

More on Emmett Till

Bulletproof replacement

Patrick Weems, executive director of the Emmett Till Memorial Commission, said the memorial site honouring Till is the subject of constant abuse.

"From the beginning, we've had an ongoing struggle to keep the memorials up," said Mr Weems. "There are obviously some folks out there who don't want this story to be told."

"For some of our community members, black community members especially, this harkens back to a bygone area, a time of intimidation and violence," Mr Weems continued.

"For me, as a white Mississippian, there's an inclination to say this is not just three lone white students. This is what happens when we don't teach our history."

Mr Weems added that the 50lb (23kg) memorial will be swapped out for a bulletproof 500lb sign made of reinforced steel. It will be dedicated on 19 October with the Till family and the Mississippi Center for Justice.