After the end of the Civil War in May 1918, captured Reds were concentrated from smaller camps into a few larger camps, of which the Ekenäs (Dragsvik) garrison was one. According to the plan, thus both food supply and guarding could be done more economically, and as the aim of the winners was to convict all Reds it would be easier and faster when the prisoners were gathered in larger camps. The number of prisoners in Ekenäs grew from under a hundred in the middle of May to just under 8 700 prisoners at midsummer. There was no capacity whatsoever to take such a large number of prisoners in the 200 x 500 metre camp separated from the garrison in terms of either food supply or accommodation. Due to the poor conditions, prisoners soon started to die of starvation and diseases. Already in June, 492 prisoners died in the camp. The bleakest numbers were recorded in July when around 1100 prisoners died, and in August when around 1040 prisoners died. Still in September, 406 deaths were recorded. Over 3 200 prisoners died in the camp, i.e. about every third prisoner that was brought to Ekenäs also got their final resting place in the biggest mass grave in Finland near the garrison.
In Finland, attention was paid to the events in the prison camp only when critical voices were heard from abroad, mainly Sweden and United Kindgom, because of the high mortality especially in the Ekenäs camp. Even then there was a reaction to the matter only because of the criticism.
On September 15th the camp was turned into a forced labour facility, and the remaining prisoners stayed there together with prisoners brought from elsewhere and convicted.
The mass grave was forgotten, perhaps also because of the shame, remaining surrounded by barbed wire and unattended, for decades until the association of former members of the Red Guards, Entiset Punakaartilaiset, began to remind of its existence.
1951 The association of former members of the Red Guards erected a memorial at the mass grave.
1952 – 1985 The association of former members of the Red Guards organised an annual visit to the grave. The tradition continued until 1985 when there were ever fewer of them left. The SKP (Finnish Communist Party) Uusimaa Discrict together with the party's Tammisaari unit was responsible for organizing the event during the years 1982-1985.
1988 The citizens’ committee founded in 1985 extended the memorial and unveiled name plaques of those in the grave based on the information then.
1993 An extra plaque with the names that were missing according to the information then was unveiled by the citizens’ committee. Bishop Erik Wikström blessed the deceased.
1998 In an event organised by the citizens’ committee, all significant parties in Finland, the Evangelical Lutheran Church of Finland and the Finnish Defence Forces honoured those buried in the mass grave.
2008 A permanent exhibition about the events in 1918 was opened in an exhibition space built for it near the memorial.
2010 An association, Tammisaaren punavankimuistomerkin hoitoyhdistys – Skötselföreningen för röda fångars minnesmärke i Ekenäs ry, was founded to keep up the traditions of the memorial and to guard and maintain the memorial and the attached area.
2012 The memorial plauqes acquired by the association (that had names of the deceased, missing from the memorial for the time, carved onto them) were revealed.
2018 marked 100 years since the civil war and was the memorial year of the civil war and the prison camp. The memorial plaques and names were updated to match the most recent findings of the association. In the memorial event held on 6th of June, the Archbishop Emeritus Kari Mäkinen gave a speech. In addition the song ”Tie” ("Road") was sang by Koiton laulu, lead by the composer of the song Tomas Takolander. On the same day a memorial seminar was held in the canteen of the local garrison.