STAMFORD, Conn. (AP) — More relatives of people shot to death at a Colorado supermarket in 2021 are suing gun-maker Sturm, Ruger & Co. over how it marketed the firearm used in the massacre, adding to litigation first filed earlier this month against the company.

The lawsuit by relatives of five of the 10 people killed in Boulder was served on the company Thursday and is expected to be filed this week in Superior Court in Stamford, Connecticut, according to Andrew Garza, a lawyer for the plaintiffs. The son of a sixth victim sued the company on March 14.

Both lawsuits accuse Sturm, Ruger & Co. of marketing its AR-556 pistol, which resembles a rifle, in a "reckless" and "immoral" way that promoted its killing capability and glorified lone gunmen. The lawsuits, which seek undisclosed damages, are expected to be consolidated into one case, Garza said.

"We're interested in pursuing justice for all the families and holding Ruger accountable," Garza said Monday.

Representatives of Sturm, Ruger & Co., based in Fairfield, Connecticut, did not immediately respond to email and phone messages Monday.

The wrongful death lawsuits are similar to one filed against gun-maker Remington by relatives of victims of the 2012 Sandy Hook Elementary School shooting that killed 20 children and six educators. That lawsuit led to a $73 million settlement with Remington last year.

Gun makers are generally shielded from liability under a 2005 federal law, but an exception allows lawsuits over firearms marketing.

The gunman in the March 22, 2021, shooting at the King Soopers store in Boulder legally bought the Ruger AR-556, investigators said.

The six victims whose relatives are suing Sturm, Ruger & Co. were Suzanne Fountain, Neven Stanisic, Denny Stong, Lynn Murray, Jody Waters and Kevin Mahoney.