This increases the overall number of suspects arrested to five.
The suspects, Dookuuri Fausta, Braimah Kasim, Beyuo Felix, and Michael Klugey, all staff at the Cossy Hill Hotel, are in police custody and are aiding the investigation, along with suspect Kumbata Kwaku, who was previously detained.
According to the authorities, the investigation will continue until all criminals are brought to justice.
This follows prior claims that Mr Johnson was assassinated by certain assailants.
Mornah Banung-kae Kennedy, a regional journalist, confirmed the occurrence on his social media page, calling the scenario unfortunate.