He did not reveal information on the citizenship of the wounded persons, just said that two of them were men and one was a woman.
Grisins said that the wounded persons were guests in the nearby guest house. They are in a hospital, in a severe condition, but stable.
He also said that the crime has been committed by several people.
As reported, the incident happened on the afternoon of September 30 near the Vitality Academy clinic in Aizpute region, in what appeared to be an assassination attempt.
The incident is in some ways reminiscent of the killing of a prominent lawyer earlier this year - with police still searching for the perpetrator - sparking speculation that the cases may be linked, though there is no hard evidence to suggest this.
Other media reports suggested the victims are Israeli but this has not been confirmed by officials.
