Late Tuesday in Greeleyville, S.C., the Mount Zion African Methodist Episcopal Church caught fire and was quickly engulfed in flames.

Including the Greeleyville church, in the two-week period since the Charleston shooting, at least half a dozen predominantly black churches have been destroyed or severely damaged by fires. Not all of the fires are considered the work of arsonists, but concerns have been raised nevertheless as to how much of June's church fires echo past racist attacks. 

Here is what you need to know about the ongoing investigations:

The investigations: The federal Bureau of Alcohol, Tobacco, Firearms and Explosives as well as the FBI have joined local fire and police departments' investigations in some of the cases including the one in Greeleyville. Three of the burnings have been identified as acts of arson by local officials, but so far there have been no arrests and the episodes are not considered linked. The New York Times named a few reasons as to why officials don't believe the the fires to be hate crimes.

June Church Fires

• June 21: College Hill Seventh-day Adventist Church in Knoxville, Tenn. -- Arson confirmed by local officials.

• June 23: God's Power Church of Christ in Macon, Ga.  -- Arson speculated by local officials.

• June 24: Briar Creek Baptist Church in Charlotte, S.C. -- Arson confirmed by local officials.

• June 26: Glover Grove Missionary Baptist Church in Warrenville, S.C. -- Ongoing investigation.

• June 26: Greater Miracle Temple Apostolic Holiness Church in Tallahasse, Fla. -- Cause thought to be an electrical short, ongoing investigation.

• June 30: Mount Zion African Methodist Episcopal Church in Greeleyville, S.C. -- Cause supected to be from lightning, ongoing investigation.

The current conversation: Though the fires are not currently thought to be racially motivated, shortly before Monday's fire the NAACP issued a warning to black churches and urged them to take precaution, referencing how they have "long battled the burning of black churches." Twitter users have used the hashtag #WhoIsBurningBlackChurches to call for further investigation as well as speculate about a possible connection between the string of church fires, the call for the removal of Confederate symbolism and the white supremacist manifesto that surfaced in the wake of the Charleston shooting.

The backstory: Almost 20 years to the day before Tuesday's fire, two members of the Ku Klux Klan burned the Greeleyville Mount Zion church down to the ground. Bill Clinton spoke at the site in 1996 when it was newly rebuilt following a slew of church burnings that previous year: "We are now reminded that our job is not done." Following the Charleston shooting and June's string of church fires, the New York Times and the Los Angeles times have published and republished pieces exploring the history of attacks on black churches and commentary on racially motivated violence. The Washington Post also published a piece about why racists target black churches.

How to help: The Christ Church Cathedral in St. Louis, Mo. has started a fundraiser for those churches confirmed as victims of arson. The fundraising website also includes a line saying that if any more black churches are attacked by arsonists, they will be added to the fundraiser.