Police secretly monitored suspect in Piia Ristikankare case

Police suspected a man living in the Turku area of murdering Piia Ristikankare, who disappeared nearly 38 years ago, Yle reports. Documents obtained by Yle from the Southwest Finland District Court show that police secretly monitored the man’s telephone calls and communications at least in 2003 and 2007.

Ristikankare, 15, disappeared from her home in Piikkiö, in the Southwest Finland region, on October 7, 1988. The National Bureau of Investigation suspects she was the victim of a homicide, but her body has never been found.

The suspect, who was born in the late 1950s, was about 30 years old when Ristikankare disappeared and lived in Southwest Finland. He became the focus of the investigation in the 2000s after police received an anonymous letter linking him to the case.

The letter, sent to Yle’s crime programme Police TV in December 2001, said that a girl who appeared unconscious was being lifted into a Volvo passenger car beside Highway 1 in Piikkiö on the evening Ristikankare disappeared. The letter included the car’s registration number. Although the writer suggested the letter had been sent from Borås, Sweden, it was postmarked in Turku.

The National Bureau of Investigation told the district court in 2007 that the sender could not be identified. However, based on the investigation, police said there was no reason to consider the tip clearly false.

Police established that the Volvo mentioned in the letter was used by a close relative of the suspect at the time of Ristikankare’s disappearance. The suspect may therefore also have had access to the car. Other possible users of the vehicle in October 1988 were also investigated.

According to a police application for coercive measures, a sniffer dog was used to examine the car’s boot in 2003. Police said the examination indicated that it was possible a body had been transported in the boot, but forensic laboratory analysis did not provide full certainty. The National Bureau of Investigation examined the Volvo again in 2023.

In July 2007, police asked the then Turku District Court for permission to intercept the suspect’s calls and obtain his call records. The case had returned to television at the time. Police believed the suspect might speak by telephone with someone who knew about his possible involvement in the disappearance.

Police told the court that traditional investigative methods were unlikely to resolve a case dating back so many years. Documents also show that the man’s telephone had been secretly monitored four years earlier, in 2003, and that police believed the surveillance had strengthened the suspicion against him.

During the 2003 surveillance, the man reportedly discussed with people close to him how they should respond if police asked about use of the Volvo. According to police, he told them to say that he had not used the car.

The National Bureau of Investigation also told the court that the suspect had a history of sexual offence allegations dating back to the 1970s. Police said he had committed rape at least three times between 1978 and 1985, with all the alleged victims being young girls. None of the cases reached a prosecutor; police said they were settled through compensation paid by the suspect. In at least one case, police said, he had also threatened to kill the victim.