The 65-year-old man, dubbed "Södermannen" by the press, was previously convicted for breaking into women's homes in Stockholm and Gothenburg and attempting to rape them.
He was arrested in 1983 and sentenced to psychiatric care for six counts of rape, although he never confessed to the crimes.
He fled the country the same year and was arrested two years later at Stockholm's Arlanda airport. In 1987, he was released from psychiatric care at Karsudden hospital.
According to the conviction issued on Tuesday, the man is guilty of having sex with the 14-year-old, despite the girl's claims that the sex was consensual.
While consensual sex with a minor can be classified as sexual abuse of a child, prosecutors argued successfully that it constituted child rape in this case because the 65-year-old man was so much older than the girl and due to the girl's vulnerable circumstances.
The court also cited the fact that the man had sex with the girl on multiple occasions and refused to use contraception.
The prosecutor had also hoped the 65-year-old would be convicted for rape for the instances he had intercourse with the girl after she turned 15, but the court instead classified the incidents as purchasing sexual services from a minor as the man paid the girl by giving her access to marijuana.
He was also convicted of narcotics offences.
The 65-year-old claimed he and the girl were in love, but the girl's legal representative disagreed.
"A 14-year-old girl who smokes and drinks and has contact with a man in his sixties isn't out looking for love," lawyer Sofia Möller told the TT news agency.
In addition to spending four years in prison, the 65-year-old has also been ordered to pay 160,000 kronor ($25,000) in damages to the girl.
The man's defence attorney expects his client will appeal the verdict.
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