KANSAS CITY, Mo. — Missouri Attorney General Andrew Bailey alleges in a lawsuit Monday that one of the utility companies involved in last month’s deadly gas pipeline explosion violated state law.

Earlier this month, investigators from the National Transportation Safety Board released preliminary findings into the April 9 gas pipeline explosion in Lexington, Missouri.

Their preliminary report questioned if Liberty Utilities, which owns the gas line, had properly marked the area prior to a contractor’s work to install fiber optic cable.

The contractor struck the gas line around 4:14 p.m., and after several hours of natural gas saturating the ground in the neighborhood, the gas ignited around 7:42 p.m., causing an explosion that killed 5-year-old Alistair Lamb and injured his 10-year-old sister, Cami, and their custodial father, Jacob Cunningham.

Bailey’s lawsuit claims that by allegedly failing to properly mark the area prior to work, Liberty Utilities violated the Missouri Underground Facility Safety and Damage Prevention Act .

Bailey called the deadly explosion a “preventable tragedy” in a press release announcing the lawsuit.

“These companies must take their responsibilities seriously,” Bailey said in the release. “The law is clear, the process is simple, and the consequences of failure are catastrophic. We’re holding Liberty Utilities accountable to ensure that every utility in Missouri does its due diligence to prevent future disasters.”

Bailey’s lawsuit is not the first lawsuit to be filed in connection with the deadly explosion.

In late April, Cunningham filed a wrongful death lawsuit against Liberty Utilities, United Fiber, LLC, Alfra Communication, LLC and Sellenriek Construction.

Both lawsuits were filed in Lafayette County Circuit Court.

"Nothing is more important to us than the safety of our customers, employees, and communities," a Liberty Utilities spokesperson said in a statement Monday to KSHB 41. "We remain fully committed to working with authorities and regulatory agencies to support the ongoing investigation into the cause of the incident."

The spokesperson said NTSB investigators have asked the utility company to be a party in the investigation . Such organizations are designated at the discretion of the NTSB to help provide expertise and technical details related to the specific investigation.

"Our thoughts and prayers remain with the affected families whose lives have been devastated by this tragedy and with the Lexington community," the spokesperson continued. "We will continue to do our part to help those affected and support broader recovery efforts."