PARIS (Reuters) - The Paris prosecutor’s office has opened an investigation into the suspected falsifying of documents at Areva’s Le Creusot foundry that manufactures parts for nuclear reactors, a judicial source said on Thursday.

The case, which alleges forgery, use of forged documents, endangerment of lives and aggravated deception, will be put in the hands of the police, the source said.

French nuclear safety regulator ASN said in October that it had asked the courts to step in to investigate after nuclear group Areva sounded the alarm in May over documentation irregularities involving 6,000 nuclear component manufacturing files.

Thousands of such documents used in the French nuclear sector dating back to 1965 are being looked at.

“We have not been informed (of the investigation) at this point,” a spokeswoman for Areva told Reuters, adding that the group would cooperate with the investigation and hand over all information at its disposal.

The discovery of weak spots in the reactor vessel of the EPR reactor under construction in Flamanville in 2014 led Areva to review manufacturing procedures at its Creusot steel forging plant.

ASN said in September that Areva had identified 87 irregularities related to reactors operated by state utility EDF, 20 concerning equipment for the Flamanville reactor, and one related to a steam generator for EDF’s 900 MW Gravelines 5 reactor on halt since April.

Gravelines 5’s restart has been pushed back to June 2017 after an executive told parliament in October that something suspicious had been discovered.