The police have sought pretrial detention warrants for four officials at lithium battery maker Aricell on charges related to the deadly fire that killed 23 people and injured eight others on June 24.  

Announcing the results of a two-month investigation on Friday, a police team tasked with probing the fire said that it has booked 18 officials and requested pretrial detention warrants for four officials, including Aricell CEO Park Soon-kwan.

The four officials face charges of violating the Occupation Safety and Health Act as well as the Serious Accidents Punishment Act and of causing death or injury by professional negligence. 

The probe found that Aricell hired a large number of unskilled workers following a delay in its delivery deadline under its contract with the Defense Acquisition Program Administration(DAPA).

The company had to reproduce goods allotted for the state defense procurement agency, after the initial delivery failed to meet standards in quality inspection in April, paying about 700-thousand won per day for the delayed delivery since May.

Total reimbursement amounted to 38 million won at the end of June, when the fire broke out. 

The firm reportedly set an excessive goal of producing five-thousand batteries a day since May 10 and hired 53 new workers and put them into the main manufacturing process without sufficient training, which resulted in a nearly three-fold increase in the product defect rate.