GRAND RAPIDS, Mich. (WOOD) The showdown between a group of hackers and a Michigan tribe is far from over, even as the tribe prepares to reopen its chain of casinos following an 18-day shutdown.

A group called RansomHub has claimed responsibility for the cyberattack and submitted a letter to the Sault Tribe Guardian on Feb. 16 to provide its “side of the events.”

The hacker group said it has made “multiple attempts” to contact the Sault Ste. Marie Tribe of Chippewa Indians and said reports that they are demanding $5 million in ransom are false.

“They have received detailed instructions via phone voicemails, corporate and personal emails and internal network messages,” RansomHub wrote in the letter. “Despite these numerous efforts, no representative from the Sault Tribe has initiatives any communication with us. Therefore, the reported $5 million ransom figure is purely speculative, as no negotiations have taken place.”

The attack was first discovered on Feb. 9, forcing the tribe to promptly shut down the Kewadin Casinos. The Sault Ste. Marie location is set to open Wednesday. The St. Ignace casino will open at noon Friday. The other three locations, in Manistique, Christmas and Hessel, will open at noon March 3.

RansomHub claims it has possession of more than 100 gigabytes of confidential data. Tribal Chairman Austin Lowes said the tribe is still working to determine the extent of what private data was stolen, but did confirm that his personal information and the private data of his family members was exposed.

“The financial situation of the tribe is sufficient to cover the expenses associated with this cyberattack,” the RansomHub letter read. “The tribe’s failure to act raises serious questions about its leaderships priorities and intentions regarding this matter.”

Lowes has not made any mention of demands from the hackers or whether the two sides have negotiated a possible deal.

The ransomware focused on the tribe’s computer networks and internal phone systems. In addition to shutting down the tribe’s five casinos, it severely limited all sorts of tribal services, including its health centers.

Ransomware is a type of malicious hardware that locks users out of computer files, systems or networks and “demands a ransom” to get it back. The FBI says there are several ways to unknowingly download ransomware onto a computer anything from opening an email attachment, a pop-up ad or even visiting a website that has embedded malware.