Tuntematon ystävä was the third attempt to film the works of popular and populist Finnish detective novelist Mauri Sariola. Based loosely on the 1970 novel Susikoski virittää ansan, the film also features his most famous protagonist, the no-nonsense, conservative Detective Inspector (later Superintendent) Susikoski. It was also probably the worst of the three.
Sariola's strong points usually lay more with his characters and typically acerbic observations about society and people than his often mechanistic and haphazard plots. Unfortunately, what Tuntematon ystävä takes from its source is mostly the heavily reworked basic plot, which in the film concerns an American-Finnish couple who murder various "society's parasites" for their insurance money.
The film does try. At the time, it was for Finnish cinema an exceptionally brazen attempt to make a mainstream commercial thriller with international cast and a climax shot in Morocco. The end result, however, is on par with a mediocre television film, which totally wastes its elite cast, including Lindholm in the title role. Staging, dialogue and attempts at suspense in fact now seem more fitting for a comedy than a thriller. Even a record-breaking marketing campaign couldn't turn the film into the hit it aspired to be.
Women get to provide the few bright spots in the overall gloom: the ex-Miss Finland Pohtamo may be hilariously incapable of acting, but Westerlund shines as a dotty would-be victim, and the long-suffering O'Mara - who was immensely popular in Finland at the time thanks to The Brothers - actually manages to work some depth into her role as a reluctant femme fatale.