The parents of Sabika Sheikh, a 17-year-old Pakistani exchange student who was killed in a Texas school shooting in May, are suing the parents of the shooter for negligently and irresponsibly storing their firearms.

Abdul Aziz and Farah Naz have joined a lawsuit in which some of the 10 victims' families are alleging that the shooter's parents knew their son was experiencing extreme emotional distress but failed to take basic steps to responsibly store and prevent him from accessing their firearms, according to a Nov 28 press release issued by Everytown for Gun Safety’s litigation team.

The petition also alleges the shooter’s parents failed to respond to and address warning signs that their son posed a risk to others.

"No other parent should ever have to experience this unbearable grief," Sabika's parents said. "For a mother and a father, this trauma and mourning stay until their last breath. We are grateful to everyone in the US and around the world who met us in person and reached us through emails, print, electronic and social media to express solidarity and empower us to endure this most profound tragedy."

The petition was filed just days before Sabika's 18th birthday on Dec 1, the press release said.

Sabika, a Karachi teenager whose family lives in the Gulshan-i-Iqbal area, was studying at Santa Fe High School in Texas on a US State Department scholarship under the Kennedy-Lugar Youth Exchange and Study (YES) programme.

She was among 10 students gunned down on May 18, 2018, inside the school by another teenager with white supremacist tendencies.

According to her father, Sabika — the eldest among three sisters but younger than her brother — was due to return home on June 9. Her family had been counting the days till her return. She was laid to rest in Karachi.