St Vincent police are searching for those who lit fires in the streets just outside her Majesty prison in Kingstown on 5 August.
On 5 August, an anti-vax protest organised by Rise Hairouna and backed by St Vincent main Opposition party took place in Kingstown.
On Sunday, 5 September, Prime Minister Ralph Gonsalves said he believes the police have evidence as to who is responsible.
However, he also believes that they are ensuring the evidence obtained is admissible in court.
Since the protest of 5 August, which left Prime Minister Gonsalves with a head wound, several opposition figures were arrested and charged under the Public Order Act.
The Opposition, the Public Service Union, and Rise Hairouna will protest on Thursday, 9 September.
St Vincent police had written to the Public Service Union indicating that protest within close proximity to the Parliament is prohibited.
The Public Service Union voted on Saturday, 4 September, to defy the police order.
However, in a letter to the PSU on Tuesday 8, the Police High Command stated that permission was granted for the demonstration.
Reasons for the about-turn was sighted as no sitting of Parliament and the High Court.