Criminal police are conducting an investigation on suspicion of crimes in cooperation with the competent district state prosecution, the Kranj Police Department told the STA on Monday.
The statement comes after the news portal Siol published screenshots of a Facebook page called "Kranjska Vahta" or Kranj Guard, echoing the name of Šiško's "Štajerska Varda" or Štajerska Guard.
The Facebook page contains three photos of what appear to be eight men in full fatigues wielding weapons, some of which are easily identifiable as AK-47 assault rifles.
The page says the photos are from an exercise that took place on 4 September, a day after Šiško's self-styled militia first came to public attention.
It is unclear as yet whether the two groups are related, but Šiško had said he was seeking to form a similar armed militias across all Slovenian regions.
Pictures of Šiško's group showed only a few men having weapons, most others were unarmed and clad in green outdoor clothing and balaclavas.
The second group looks like they are dressed in full army fatigues, one is seen wearing a helmet and several others were wearing tactical vests.
Photo: Kranjska Vahta's now removed Facebook page
While the photos disappeared from Facebook later in the day, the page now features a message saying "this was a media experiment designed to test mass media's reaction".
Nevertheless, the police said they were investigating the incident with all due care and within their powers.
The police also called on the author of the Facebook page to report to the police to clear up the situation, but added that no person had been detained so far.
It is unclear whether the two groups are related, but Šiško had said he was seeking to form similar armed militias across all Slovenian regions.
Šiško was arrested on 6 September on suspicion of inciting to violent subversion of the constitutional order, and remains in custody due to the risk of re-offending.
