WASHINGTON >> Relatives of the victims of two fatal Boeing 737 MAX crashes asked the Justice Department on Wednesday to seek a fine against the planemaker of up to $24.78 billion and move forward with a criminal prosecution.

“Because Boeing’s crime is the deadliest corporate crime in U.S. history, a maximum fine of more than $24 billion is legally justified and clearly appropriate,” Paul Cassel, a lawyer representing 15 families, wrote in a letter to the Justice Department released on Wednesday.

The families said the Justice Department could potentially suspend $14 billion to $22 billion of the fine “on the condition that Boeing devote those suspended funds to an independent corporate monitor and related improvements in compliance and safety.”

The Justice Department said in May it determined Boeing violated a 2021 deferred prosecution agreement that shielded the company from a criminal charge of conspiracy to commit fraud arising from fatal crashes in 2018 and 2019 that killed 346 people.

Boeing last week told the government it did not violate the agreement. Federal prosecutors have until July 7 to inform a federal judge in Texas of their plans, which could be proceeding with a criminal case or negotiating a plea deal with Boeing. The Justice Department could also extend the deferred prosecution agreement for a year.

Justice Department officials found that Boeing violated the deferred prosecution agreement after a panel blew off a new Alaska Airlines Boeing 737 MAX 9 jet on Jan. 5, just two days before the 2021 agreement expired. The incident exposed continued safety and quality issues at Boeing.

In the letter, the families also said Boeing’s board of directors should be ordered to meet with them and the department should “launch criminal prosecutions of the responsible corporate officials at Boeing at the time of the two crashes.”

Boeing and the Justice Department did not immediately comment.

The letter noted that Senator Richard Blumenthal, who chairs the Senate’s Permanent Subcommittee on Investigations and held a hearing with Boeing CEO Dave Calhoun on Tuesday, said, “There is near overwhelming evidence in my view as a former prosecutor that prosecution should be pursued.”

The two fatal crashes of Boeing 737 MAX planes occurred in 2018 and 2019 in Indonesia and Ethiopia and led to the best-selling plane’s worldwide grounding for 20 months. A safety system called MCAS was linked to both fatal crashes.