A woman whose nine family members died when a duck boat sank in Missouri on July 19 is alleging in a new lawsuit that the operators knew that the design of canopies on the vehicles could create a “death trap” for passengers.

The lawsuit, filed on Tuesday in federal court in Missouri, joins at least six others brought by survivors and family members of the victims of the sinking, in which 17 of the 31 people on board drowned. The Missouri Attorney General's Office also brought a suit last week. Like many of the lawsuits, the case alleged negligence and strict products liability claims, asserting that Ripley Entertainment Inc. and previous tour operators were aware since 1999 that the design of the duck boats were unsafe.

Andrew Duffy, of Philadelphia's Saltz Mongeluzzi Barrett & Bendesky, filed Tuesday's suit for Tia Coleman on behalf of her husband, two sons and daughter, who were among the nine members of her family who died.

“The focus of the case is making sure this never happens to another human being,” Duffy said. “These duck boats have now killed over 40 people since 1999.”

A spokeswoman for Ripley, which is based in Orlando, referred requests for comment to the website bransonducks.com, which offered condolences to “all that have been affected.” The website stated: “The business has not operated since the incident so we can take time to focus on our guests, employees and families who were affected by the accident. We remain committed to supporting our guests, families and employees who were affected. To assist families in their time of need, we continue to offer to pay for all related medical bills, funeral expenses and grief counseling.”

In addition to lawsuits, the duck boat sinking has prompted a criminal investigation by the U.S. Attorney's Office for the Western District of Missouri. On Aug. 29, federal prosecutors in that office filed motions to intervene in at least three of the lawsuits in order to stay discovery pending its criminal investigation, insisting that it's “virtually inevitable that any discovery sought in this case will interfere with the government's investigation.”

The suits claim a National Transportation Safety Board report recommended that duck boats remove their canopies and add reserve buoyancy to make them safer. That report followed the 1999 sinking of a duck boat in Hot Springs, Arkansas, that killed 13 people.

Duffy said there's “no credible claim” that a duck boat operator wasn't aware about the deficiencies in the canopies. “Unfortunately, there are still canopies across the country,” he said. “Some operators claim to have changed that. We have not seen what yet that we deemed acceptable.”

Also, according to his latest suit, Ripley's made no changes to the duck boats when it acquired the company in 2017, even after an inspector recommended safety improvements.

The latest case, along with prior lawsuits, also brought claims under the Missouri Merchandising Practices Act, alleging Ripley made false assurances of safety to its customers.

At least one other suit named the captain and driver of the boat, one of whom was among the 17 victims. Despite an impending thunderstorm, the duck boat went out into the water, instead of canceling the tour, and the captain told passengers they did not need to wear life jackets.