Quebec's provincial police have announced they will not re-investigate a 23-year-old murder case.

After a three-week analysis of the Theresa Allore murder case, police have determined there is not enough new evidence to re-open the case.

Theresa Allore was attending Champlain College

But the news hasn't quelled her brother's quest to find out what happened to his sister.

Theresa Allore was reported missing Nov. 3, 1978, and her body was found in a creek near Compton, in the Eastern Townships on April 13, 1979. Her body was face-down in the water, wearing only a brassiere and underwear.

The body was so badly decomposed, the police could only conclude she died a "violent death of undetermined nature."

Photo taken just two months before she went missing

"My father had to go to the medical laboratory to identify the body," John Allore remembers. "Our whole family was with him and I remember him walking down the hallway to do the identification and coming back ... he walked in one man and came out another man."

The mystery

At the time, John was 14 years old, living with with his parents in St. John, New Brunswick.

His sister had moved to Lennoxville, Que. just two months before to study science at Champlain College.

On November 3, 1978, a friend saw Theresa on the stairs of the student residence. And then, she disappeared.

"Quite possibly someone who had waited around or possibly just someone from the area, took her and grabbed her, and killed her," says Allore.

Drug overdose?

When Theresa's body was found, more than five months later, Roch Gaudreau got the call. He's a retired Sherbrooke police officer.

"Each time when I pass here and I stop on the bridge and think about the case .. when we haven't solved a crime, it bothers you," says Roch Gaudreau,

Gaudreau has a theory: 20 years ago, parties and drugs were common at the Champlain residence.

"I'm still believing," Gaudreau says, "that accident was caused by a drug overdose".

No drugs were found in Theresa's body, and yet that's how the case was left.

Hunting down a killer

John Allore has been searching through books and information for years, with a faint hope drives him that somewhere, there might be a clue to his sister Theresa's death.

"My sister was found in four inches of water wearing a brassiere and panties," says John Allore. "That's the first thing that leads me to believe it's a sex crime."

"This is my sister's watch that she was wearing when her body was found," Allore says, holding a small, worn watch. "It's a cheap Timex, not waterproof. And the time on it: it stopped at five minutes to midnight."

Connecting the dots

John Allore thinks his sister was the victim of serial killer. He sees a link between his sister's death, and two others.

Manon Dubé, 10, disappeared from a playground in downtown Sherbrooke just 10 months before. She was found face down in a stream near Ayer's Cliff.

Louise Camirand, who was last seen outside her Sherbrooke apartment, was raped, strangled, and found in a snow drift near Magog.

"When you plot those on a map ... the proximity of the roads, it's astounding," he says.

The Sûreté du Québec looked over the files of the three cases, seeing if it can find enough evidence to re-investigate. However, with a case so old, with no DNA evidence, police are relying on the chance someone might come forward.

The odds are against John Allore. Still he keeps searching.

Allore has set up a Web site at www.whokilledtheresa.com for anyone who might have information on his sister's death.