McElduff in eye of storm caused earlier row with comments over Provo linked to atrocity
This is not the first time Sinn Fein's Barry McElduff has been caught up in controversy linked to the Kingsmill massacre.
In February 2015 the then Assembly Member sparked unionist fury when he suggested that hunger striker Raymond McCreesh deserved international recognition more than some Irish Nobel prize winners.
McCreesh, who was convicted of IRA membership and attempted murder, had been arrested carrying a weapon used in the slaughter of the 10 Protestant workmen in 1976.
McElduff (51) - known for his comedic character - wrote on his blog that for many people McCreesh was "a hero and a martyr".
McCreesh has become a hate figure for unionism again in recent years after Newry and Mourne District Council named a children's playground after him.
Mr McElduff had, until now, been regarded as a canny user of social media, using a blog, Twitter and Facebook to maintain a high profile. He has almost 16,000 followers on Twitter and has tweeted almost 12,000 times.
Last April he posted a video of himself on Stormont's third floor on a mission through "no man's land" into "DUP territory" to get to the vending machine for a Snickers bar. It was viewed many tens of thousands of times.
In December 2015 Mr McElduff agreed to pay back nearly £900 to the Assembly. He was found to have broken rules by using Stormont allowances to send out hundreds of letters to constituents urging them to "stand united together against Tory cuts".
Mr McElduff was the MLA for West Tyrone from the first Assembly election in 1998 until 2017. Last year the fluent Irish speaker replaced veteran republican Pat Doherty as the MP for the constituency.