The widow of Los Angeles basketball great Kobe Bryant filed a wrongful death lawsuit on Monday against the operator of the helicopter that crashed in foggy weather last month, killing her husband, their 13-year-old daughter and all seven others aboard.

The 72-page complaint was filed in Los Angeles County Superior Court as Vanessa Bryant was joined by thousands of mourners paying tribute to the former Los Angeles Lakers star at a memorial service at the Staples Center, the team's home arena.

The lawsuit, which seeks unspecified general and punitive damages, named as defendants Island Express Helicopters, its holding company and the heirs of its pilot, Ara Zobayan, who was one of those who died in the Jan. 26 crash.

Island Express declined to comment on the litigation.

The complaint alleges 28 counts of negligence and breach of duty, accusing the defendants of failing to exercise "ordinary care in piloting the subject aircraft" and "in providing proper and safe aircraft services."

Among the specific allegations made in the lawsuit, it says Zobayan "failed to properly monitor and assess the weather prior to takeoff," "failed to abort the flight when he knew of the cloudy conditions" and "failed to keep a safe distance between the helicopter and natural obstacles."

It also alleged that Zobayan, an experienced pilot and instructor, improperly piloted the helicopter by visual orientation under limited-visibility conditions that require instrument-guided navigation.

The crash occurred "as a direct result of the negligent conduct of Zobayan for which defendant Island Express Helicopters is vicariously liable in all respects," the lawsuit said.

Although Zobayan was licensed to fly by instruments in poor weather, Island Express was only permitted to fly by visual flight rules when carrying paying passengers, the National Transportation Safety Board (NTSB) said in its initial report on the crash.

The Federal Aviation Administration rebuked Zobayan for violating visual flight rules during a 2015 incident in which he entered restricted airspace without authorization.

The luxury Sikorsky S-76B helicopter slammed into a hillside northwest of Los Angeles and burst into flames while Bryant and his entourage were en route to a youth sports academy for a girl's basketball tournament.

Gianna Bryant, the second of Kobe and Vanessa's four daughters, was a member of the team due to compete that day. Her father, who retired in 2016 after 20 years with the Lakers, was the team's coach.

The NTSB's initial crash report did not identify any obvious signs of engine failure or other mechanical problems that may have contributed to the tragedy, but it confirmed reports of low clouds and fog at the time the accident occurred.

The NTSB also said the helicopter was not equipped with any kind of "terrain awareness and warning system," which might have alerted the pilot that the aircraft was getting dangerously close to the hillside.