US cybersecurity firm Mandiant, which is owned by the California-based company FireEye, has said that it has found no evidence so far of substantive contact, direct email or financial links between a Russian bank and Republican presidential candidate's Trump Organization. Moscow-based Alfa Bank had hired the company to investigate its systems and records following allegations of secret communications between an email server operating Trump domain addresses and the bank's server.

The bank is owned by Mikhail Fridman and Pyotr Aven. Aven worked with Vladimir Putin back in the early 1990s in the St. Petersburg government.

Earlier this week, Slate published an article about an alleged secret line of communication between the servers, indicating a "sustained relationship" between Donald Trump and Russia's largest private commercial bank. Citing multiple cybersecurity experts, the report suggested that "the communication wasn't the work of bots," but seemed to be a "pattern of human conversation" that began "during office hours in New and continued during office hours in Moscow."

The researchers quoted in the article said Trump's server was "set up to accept only incoming communication from a very small handful of IP addresses. They also said 87% of the DNS lookups involved Alfa's Bank's servers.

"The parties were communicating in a secretive fashion," software expert and internet pioneer Paul Voxie told Slate. "The operative word is secretive. This is more akin to what criminal syndicates do if they are putting together a project."

Donald Trump
Republican presidential nominee Donald Trump holds a campaign event in Eau Claire, Wisconsin US November 1, 2016. Carlo Allegri/Reuters

The Clinton campaign dubbed the report evidence of "the most direct link yet between Donald Trump and Moscow." Hillary for America senior policy adviser Jake Sullivan said on Monday, "This secret hotline may be the key to unlocking the mystery of Trump's ties to Russia." The Trump campaign, however, denied the allegations.

"The email server, set for marketing purposes and operated by a third-party, has not been used since 2010," the Trump campaign said in a statement to multiple media outlets. "The current traffic on the server from Alphabank's [sic] IP address is regular DNS server traffic - not email traffic.

"To be clear, the Trump Organization is not sending or receiving any communications from this email server. The Trump Organization has no communication or relationship with this entity or any Russian entity."

Mandiant said it analyzed the internet server logs given to Alfa Bank by media organisations investigating the communications. After going through the log of the communication between the servers over a period of 90 days, FireEye said it found the information presented "inconclusive."

"The information presented is inconclusive and is not evidence of substantive contact or a direct email or financial link between Alfa Bank and the Trump campaign or Organization," FireEye said in a statement, The Guardian reports. "The list presented does not contain enough information to show that there has been any actual activity opposed to simple DNS lookups, which can come from a variety of sources including anti-spam and other security software.

"As part of the ongoing investigation, Alfa Bank has opened its IT systems to Mandiant, which has investigated both remotely and on the ground in Moscow. We are continuing our investigation. Nothing we have or have found alters our view as described above that there isn't evidence of substantive contact or a direct email or financial link between Alfa Bank and the Trump campaign or Organization."

In the Slate article, the author noted that the New York Times was investigating the link as well. The Times reported on Monday that after weeks of investigation, the FBI dismissed the idea of a possible secret communications channel between the two servers, concluding that "there could be an innocuous explanation, like a marketing email or spam, for the computer contacts."