Clive Sharp, 46, harboured fantasies of imprisoning and killing women, Mold Crown Court heard yesterday.
Sharp left one woman tied to a bed after she refused his demands, then hours later killed his victim.
He crept into the house of Ms Gowing at night before tying her to the bed and repeatedly raping her. After killing his victim, he mutilated her and dismembered the body.
Sharp had twice been jailed for sex offences before he attacked Ms Gowing.
The victim, described as a "vibrant, wonderful woman" had the "great misfortune" of being good friends with the killer's then-girlfriend.
Sharp, who admitted murder last month, was told by judge Mr Justice Griffith Williams he would serve a minimum of 37 years behind bars before being eligible for parole. "This is a horrific, cold-hearted murder, carried out to gratify your perverted sexual desires," the judge told Sharp.
"You are, on any view, a very serious danger to women."
Dressed in grey jogging bottoms and a grey jumper, the defendant made no reaction as he was jailed.
Andrew Thomas QC, prosecuting, told the court: "He killed her, then mutilated her body by cutting it into pieces and disposing of the body in and around the River Dee."