South Korea's prosecution will convene a committee this week to determine the validity of its investigation into Samsung's de facto leader Lee Jae-yong over a controversial merger and accounting fraud.

According to the Seoul Central District Prosecutors Office, the committee, made up of 15 outside experts, will meet at 10:30 a.m. Friday to review the issue and listen to presentations by the two sides -- Samsung Group and the prosecutors.

The expert group will go over lengthy written opinions submitted on site by the two sides, followed by sessions in which prosecutors and Lee's lawyers will take turns giving a presentation.

A decision is expected to come out late in the day after internal discussions. In case the committee turns out to be equally divided on the issue, no conclusion will be made.

The review process by external experts was established after a citizen's panel, formed by the prosecution, arrived at a decision on June 11 that the issue needed to be reassessed.

Early this month, Lee requested a public assessment on the investigation, an outside review system introduced two years ago to enhance neutrality and fairness of prosecutorial probes into cases that are of great public interest.

Lee, vice chairman of Samsung Electronics, is under a probe for allegedly playing a role in the controversial merger in 2015 between two Samsung affiliates, Cheil Industries Inc. and Samsung C&T, and the suspected accounting fraud at the pharmaceutical unit of Samsung Biologics.

The prosecutors suspect that the merger and fraud were designed to help him gain greater control of the country's biggest conglomerate.

Lee is the grandson of Lee Byung-chull, the founder of Samsung Group. His father, Lee Kun-hee, has been incapacitated since he suffered a heart attack in 2014.

On June 9, the Seoul Central District Court rejected the prosecution's request to put Lee behind bars for a further probe into the case. 

It said there was "insufficient explanation on the need and validity to arrest the defendants against the principle of trial without detention," referring to the principle that pretrial detention should only be used as a last resort. The court also said whether Lee is guilty should be determined through "legal battles and court hearings."

Although not legally binding, a conclusion by the committee is likely to affect the prosecution's legal actions against Lee.

Since the introduction of the system, the committee gave out recommendations in eight cases and the prosecution followed all of them. But some expect the prosecution, having shown confidence all along to prove him guilty, to push ahead with its plan to indict Lee on stock manipulation and violation of capital laws.

Lee has denied the allegations against him. Samsung also has claimed that Lee was not briefed on and did not order any illegal transactions, including stock manipulation and accounting fraud. (Yonhap)