The drama is heating up between CrowdStrike and Delta Airlines amid a potential lawsuit against the technology company after July’s mass outage that allegedly led to the cancelation of thousands of Delta flights.

On Sunday, CrowdStrike’s lawyer Michael Carlinsky reportedly wrote to Delta Airlines’ lawyer David Boies that Delta’s threats of a lawsuit “contributed to a misleading narrative that CrowdStrike is responsible for Delta’s IT decisions and response to the outage.”

The letter alleged that CrowdStrike CEO George Kurtz reached out to Delta CEO Ed Bastian amid the disaster to “offer onsite assistance, but received no response,” per CNBC.

Related: Read the Memo from CrowdStrike Explaining Massive IT Outage

Carlinsky also said that should Delta go forward with the lawsuit, the airline would have to “explain to the public, its shareholders, and ultimately a jury why CrowdStrike took responsibility for its actions—swiftly, transparently, and constructively—while Delta did not.”

Last week, Bastian spoke to “Squawk Box” and said that the airline had “no choice” but to seek damages following the incident.

“We have to protect our shareholders,” Bastian said on the show. “We have to protect our customers, our employees, for the damage, not just to the cost of it, but to the brand, the reputational damage.”

The CrowdStrike update caused widespread outages on Microsoft-run devices and internal issues at Delta, affecting one of the airline’s top crew-tracking tools.

Delta reportedly lost between $350 million and $500 million during the outages and canceled roughly 7,000 flights.

Related: Delta Hires Famous Attorney, Seeks CrowdStrike Compensation

Delta has not disclosed how much it would seek in compensation from CrowdStrike, and the lawsuit has not yet officially been filed. Still, Bastian told employees via an internal memo last Friday that the airline was “planning to pursue legal claims” against the tech company.

Delta Airlines was down over 15.5% year-over-year as of Tuesday afternoon.