Osellanie. He was a completely evil being. His multiple ex-wives had nothing good to say about him... The two girls he abused were his stepdaughters... After his arrest and conviction, his son spiraled out of control and spent much of the 1990s drunk and getting into trouble with the law... It was a cancer that spread to everyone close to him...
Personally, I'm less convinced of his involvement in Joanne's disappearance than in the other three cases. Still, there's enough evidence to make him a very reliable suspect...
Frank's modus operandi appears to be assault, rape, murder, and arson... If he had killed Joanne, wouldn't he have set her on fire like the other girls? Joanne was 22, and his other victims were children, although Laureen was 19, and her murder fits his modus operandi... However, Joanne disappeared in 1978, and the other three cases mentioned occurred in 1989, 1987, and 1986... It's possible he changed his methods over the years, but it still seems odd that he killed Joanne almost 10 years before his other possible victims, which occurred within a span of 3 years... Still, he seems the most likely suspect based on the information available...
whatever
Rest in peace, Joanne