SpaceX has narrowed down the rocket flaw that caused a catastrophic launch pad explosion about two months ago.

The private space company led by billionaire Elon Musk announced on Oct. 28 that investigation on the explosion has been further narrowed to one of the pressurized helium containers located in the second-stage oxygen tank.

During previous testing, SpaceX has managed to replicate a system failure, noting that the flaw might be caused by helium-loading conditions, such as temperature and pressure. More tests will be conducting more tests in the company's Texas facilities to pinpoint the root cause.

"Since the incident, investigators from SpaceX, the FAA, NASA, the US Air Force and industry experts have been working methodically through an extensive fault tree to investigate all plausible causes," the company said in a statement. "As part of this, we have conducted tests at our facility in McGregor, Texas, attempting to replicate as closely as possible the conditions that may have led to the mishap."

Previous investigation of the anomaly pointed to a large breach in the cryogenic helium system of the liquid oxygen tank in the Falcon 9's second stage. The incident was the second Falcon failure in just over a year. In June 2015, a Falcon 9 rocket loaded with supplies for the International Space Station (ISS) exploded shortly after liftoff.

"SpaceX's efforts are now focused on two areas - finding the exact root cause, and developing improved helium loading conditions that allow SpaceX to reliably load Falcon 9," the company said in the same statement.

Falcon rockets are currently grounded as the company conducts further investigation along with NASA, the Air Force, the Federal Aviation Administration (FAA), and industry experts.

The rocket exploded on its launch pad at Cape Canaveral Station in Florida on Sept. 1 during a routine test firing, which destroyed the Facebook-commissioned Amos-6 satellite it was carrying.

SpaceX is also hoping to return to flight by the end of the year, pending the results of the investigation. The company plans to resume stage testing in Texas in the coming days as the investigation progresses.