Norway’s Statoil began an investigation earlier this week into January’s assault at its In Amenas gas plant in Algeria, Wall Street Journal (WSJ) reported late on Tuesday.

The In Amenas plant, which is jointly operated by Statoil and Algerian energy company Sonatrach–was attacked in January 16 this year.

It took Algerian armed forces a few days to combat the assailants and weeks to prove the identity of the dead. In total, 40 people were murdered and 12 Statoil employees lived to tell the tales.

“We will investigate to determine the chain of events before, during and after the terrorist attack,” WSJ quoted Statoil Chairman Svein Rennemo as saying. “It has been important for us to obtain external expertise on terrorism and security.”

“The terrorists, and no one else, are responsible for the attack. They stand guilty of causing all the anguish and suffering,” Rennemo said. “Our responsibility is to learn and do what we can to further strengthen the safety of our employees for the future.”

According to WSJ, the investigation will evaluate Statoil’s risk assessments and emergency preparations, as well as the security arrangements at In Amenas prior to the attack. The company’s procedures after the attack will also be examined.

Statoil is an international energy company with operations in 35 countries. It has 40 years of experience from oil and gas production on the Norwegian continental shelf.

It is headquartered in Norway with about 21 000 employees worldwide and are listed on the New York and Oslo stock exchanges.