Eight days ago SONY (NYSE:SNE) Pictures Entertainment suffered a nasty cyber attack. The Hollywood studio was still seeking to recover some systems on Tuesday evening. The investigation is still in progress in order to find out the offender.

A few employees at the SONY corp (NYSE:SNE) entertainment unit were granted new computer systems in order to replace the effected ones that were attacked by a lethal data-vanishing virus.

The studio’s co-chiefs, Michael Lynton and Amy Pascal admitted that an immense amount of personal data including highly sensitive data has been robbed by the attackers.

According to experts, this is the first notable attack on a U.S. company which is done by intensely lethal and malicious software. This software is specially built to make the computer networks unworkable.

Interestingly, according to a U.S. national security official, the multiple suspects in this case considered by the government investigators and the FBI include North Korea. FBI also stated that they are investigating in the Hollywood studio’s home country, Japan.

The attack, which took place on 24 November, affected only those computer systems which were running on Microsoft Corp.’s (NASDAQ:MSFT) Windows operating system. Those which were working on Apple Inc’s (NASDAQ:AAPL) Mac were not harmed by the virus.

The internal computer network of SONY Pictures Entertainment (NYSE:SNE) was shut down last week to avoid further damage and forcing its employees to do all the work manually. The studio has restored a few computers to get things back on track. Especially to focus on those from which they produce revenue.

These are tough times for SONY (NYSE:SNE) as they recently suffered another attack on SONY’s PlayStation network which resulted in denial of service to its PlayStation users. People behind this cyber attack have leaked high-quality copies of SONY (NYSE:SNE) films in the last few days which are yet to be released. Moreover, SONY’s sensitive data is also made available for the public.

Chief executive of cyber security firm Packetninjas, Daniel Clemens revealed that the he observed the released files and believes they were stolen from SONY (NYSE:SNE) along with employee detail.The U.S national security official revealed that the forensic investigation is at its initial stages and no solid evidence has been found yet.

According to reliable sources, SONY (NYSE:SNE) is also monitoring whether the hackers working for North Korean government are accountable for this offence because the company was backing a film “The Interview” whose story surrounds around the North Korean leader Kim Jong Un. The film is set to release on 25 December in the U.S and Canada. North Korean officials have several times shown their concerns over this movie. If that is the case, it could be the first known case in which a nation uses its hacking abilities to cause a major blow to a company in United States.

The investigation process could take months and nothing can be predicted easily but a few media outlets mentioned the possibility of current or former employees being involved in this cyber attack too.