Family members of two people who died along with Kobe Bryant, his daughter and four other passengers in a Jan. 26 helicopter crash that also killed the pilot, joined the NBA star’s widow and other survivors in filing court papers alleging wrongful death by the company that owned and operated the aircraft.

The lead plaintiff in the still unofficial Los Angeles Superior Court lawsuit is Christopher Chester, whose 45-year-old wife, Sarah, and 13-year-old daughter, Payton, died in the crash. His two minor twin sons are also plaintiffs.

The defendants are Island Express Helicopters Inc., its owner, Island Express Holding Corp., and the estate of the pilot, Ara George Zobayan.

Representatives for the defendants could not be immediately reached.

In February, Bryant’s widow, Vanessa, the mother of their 13-year-old daughter Gianna, also filed a similar lawsuit against the helicopter company. Subsequent suits were filed in April by the families of Orange Coast College baseball coach John Altobelli, his wife, Keri, and their basketball-playing daughter Alyssa, as well as Mamba Academy basketball coach Christina Mauser.

All of the suits allege the defendants were negligent in the operation and maintenance of the Sikorsky S-76B helicopter.