A fifth suspect was killed during the police operation.
The names of those arrested were Benjamin Lodo, 17, Divine Zanu, 23, Andrew Zanu, 24 and Mawuli Zanu, 24.
They are currently in police custody assisting in investigations and being processed for court.
Throwing of objects
Briefing newsmen in Koforidua last Wednesday, the Eastern Regional Police Public Affairs Officer, Assistant Superintendent of Police (ASP) Mr Yaw Nketia-Yeboah, said about midnight last Wednesday, the suspects threw objects into a moving vehicle to compel the driver to stop.
He said when the driver stopped, the robbers attacked the passengers with machetes.
He said unfortunately for the robbers, some policemen on board the vehicle opened fire and in the process injured one of the assailants while the rest managed to escape.
Dead on arrival
Mr Nketia-Yeboah said the wounded robber was sent to the Nsawam Government Hospital for treatment but he was pronounced dead on arrival.
He said when a police patrol team went to the crime scene at about 4a.m., Benjamin Lodo and Divine Zanu were heard discussing the sequence of the encounter.
He said considering the detailed rendition of the series of events by the two persons, the patrol team became suspicious and invited Lodo and Zanu for questioning.
According to Mr Nketia-Yeboah, the suspects took to their heels upon the invitation of the police.
He said the patrol team managed to arrest the two who then led the police to arrest Andrew Zanu on whom nine mobile phones without chips in them were found.
He said two masks and a quantity of dried leaves suspected to be Indian hemp, one tigo chip and an Airtel chip were also found on Divine Zanu.
He said Mawuli Zanu was also arrested in the same house.
Mr Nketia-Yeboah said the command had recorded 10 robberies that had occurred along the Nsawam-Kumasi Highway this year, including a robbery attack on Mr Kwasi Agyemang Gyan-Tutu, the Member of Parliament for the Tain Constituency.
He, therefore, cautioned motorists to desist from stopping at secluded areas on highways, particularly around communities bordering Nsawam including Dobro, Afutu, Govinakrom and Sekyikrom.