A man in his late 40s died in a police cell in Espoo on Wednesday night, according to the Espoo Police Department.
A press release from the agency said that staff immediately started attempts to resuscitate the man after finding him to be unresponsive during a cell check. Police said that a first aid unit also promptly responded to the situation.
The incident will be investigated by the Helsinki Police Department, according to police in Espoo.
Earlier this year two other men died while being held in Helsinki police cells within a few days of each other.
In July, it was reported that the prosecutor in charge of the first Helsinki jail cell case suspected there was reason to believe excessive force was used in relation to the fatality.
According to news agency STT, last summer a periodic report issued by the UN Committee for the Prevention of Torture suggested that Finnish law enforcement staff may lack specialised training to provide appropriate care to detainees, particularly for "intoxicated persons".
"The Committee regrets the lack of comprehensive information and statistical data on the total number of deaths in custody for the period under review, disaggregated by place of detention, the sex, age and ethnic or national origin or nationality of the deceased and the cause of death, and the insufficient information on investigations carried out in that regard," the report read.
The National Police Board's Inspector Konsta Arvelin told STT in July that the board plans to update its internal guidelines this year in order to reduce deaths in police cells.
According to Arvelin, the aim is to monitor detainees' health conditions more closely.