The new suspicions bring the total number of suspects in the case to 13.
Investigators allege that the four new suspects unlawfully deprived people of their liberty and abducted them as part of a group acting under a prior agreement, causing physical suffering to the victims.
They are suspected under Part 2 of Article 146 of Ukraine’s Criminal Code.
The SBI said law enforcement officers had already exposed nine alleged members of the group in June, including six employees of the same recruitment center and three representatives of a local civic organization.
Investigators found that the group allegedly organized the unlawful transport of men to recruitment center premises and held them there against their will.
Representatives of the civic organization allegedly helped locate individuals and collected information about them.
Law enforcement officers also documented cases of alleged abuse.
Investigators said the victims were “unlawfully detained, beaten, intimidated and subjected to psychological pressure.”
A court ordered the nine previously detained suspects held in custody without bail.
They are suspected of torture, unlawful deprivation of liberty and robbery committed by an organized group under Part 3 of Article 127, Part 2 of Article 146 and Part 4 of Article 186 of Ukraine’s Criminal Code.
The pretrial investigation is ongoing.
The SBI said investigators are establishing the full circumstances of the case and examining whether other people may also have been involved in the alleged crimes.