A leading republican politician in the US has threatened to issue subpoenas against two employees of an IT firm that managed Hillary Clinton's private email server if they fail to appear before a government committee by Friday (23 September).

The employees - Paul Combetta and Bill Thornton of Platte River Networks – have been summoned by Rep Lamar Smith, the chairman of the Committee on Science, Space and Technology, after revelations emerged this week from Reddit that appeared to show Combetta colluded to delete a slew of private emails.

As previously reported, internet sleuths uncovered old posts on the popular forum that are alleged to have been written by Combetta under the name 'Stonetear'. In the initial posts, from 2014, the user asked for advice about how to delete email messages over 60 days old and also remove identifying markers of a "very VIP" client.

"If true, these details raise new questions as to whether Platte River Networks purposefully defied legal document retention requirements. Further, it is unclear if the Federal Bureau of Investigation was aware of these facts at the time of their investigation," Smith wrote in a letter sent to the IT firm's legal counsel.

"I am concerned that Mr Combetta may have made an attempt to delete relevant posts, including the post mentioned above, from his Reddit.com username just hours after reports initially surfaced on September 19, 2016, about his request for assistance on deleting email addresses from archived emails."

Online, multiple posts have appeared linking Combetta to the 'Stonetear' pseudonym. These include a 2011 Etsy profile called stonetear that is listed under the name Paul Combetta, an email account under the same name, while Stonetear's Reddit history – since deleted – made reference to Rhode Island, the place where the IT specialist once lived.

The posts on Reddit were uncovered on Monday (19 September) and quickly caused a stir online. The Stonetear user attempted to delete the contents of their profile however every post was archived by eager onlookers.

"This raises significant concerns that materials directly related to the Committee's investigation and responsive to its outstanding requests are being actively destroyed in an attempt to conceal relevant information from coming to light," Smith's letter said.

Yet Smith's committee is not the only one investigating the possibility that Combetta is the same person using the stonetear identity to post online. As noted by The Hill, the House Oversight Committee is also reviewing the Reddit claims.

Rep. Mark Meadows, chairman of the panel's Government Operations subcommittee, said: "The Reddit post issue and its connection to Paul Combetta is currently being reviewed by OGR staff and evaluations are being made as to the authenticity of the post.

"If it is determined that the request to change email addresses was made by someone so closely aligned with the Secretary's IT operation as Mr Combetta, then it will certainly prompt additional inquiry. The date of the Reddit post in relationship to the establishment of the Select Committee on Benghazi is also troubling."

Previously, the Justice Department granted Combetta immunity amid the investigation into Clinton's private emails, a deal which has reportedly frustrated Republicans who have called for a further probe to be launched into the deletion allegations. In July, the FBI recommended that Clinton and her close aides should not face charges relating to the email scandal.

This video was posting showing Stonetear's posts being deleted in real-time:

