THE crimes shocked a city and a nation.

Eight prostitutes were brutally murdered in Glasgow between 1991 and 2005. There was speculation there was a serial killer on the loose and the murders eventually led to the end of city's notorious redlight area.

Last night, however, more than a decade after the murders ended prosecutors dramatically revealed that they are now considering ordering police to re-open their investigation into the murder of Emma Caldwell - the last of the sex workers killed, and the most high profile victim.

Also last night, calls went out for a cold case review of all the deaths which brought terror to the once notorious redlight area of Glasgow.

Despite high-profile murder investigations at the time of the killings, only one resulted in a conviction, leading to calls last night from former police officer turned politician, John Finnie the independent MSP, for a fresh cold case review into the killings.

Finnie believes "fresh eyes" may be the key to catching whoever is responsible for the spate of killings, which all these years later still leave a dark cloud hanging over the city.

Eight prostitutes - including Emma Caldwell - died in suspicious circumstances in Glasgow between 1991 and 2005, but only one man has been convicted of one killing. In 2001, Brian Donnelly was jailed for life for murdering Margo Lafferty.

Finnie told the Sunday Herald: "Given the number of unsolved homicides - and the close link between them - I think these cases are worthy of a cold case review. There are common aspects among these cases, including the geography and the circumstances are the same."

Research into some of these deaths reveal striking similarities. Karen McGregor, 26, Leona McGovern, 25, Jacqueline Gallagher, 26 and Emma were all young women, working as street prostitutes in Glasgow city centre. All were throttled and their bodies dumped. They paid the ultimate price for their poverty.

However, one police source claimed that the murder of a prostitute, especially one addicted to drugs, was among the most difficult crimes to solve.

They said: "Prostitutes lead chaotic lives, a lot of them don't know if it's New York or New Year, which makes it incredibly difficult to get information and build a decent case.

"Most murders are committed by somebody you know, there is usually a relationship linking the victim and the killer. But these women come into contact with some many different men, it boils down to one stranger killing another stranger.

"This throws up problems with evidence and forensics. And you can imagine how few and far between reliable witnesses are. One lot are punters who don't want to come forward and admit they were with the prostitute.

"And the other are women, leading very chaotic lives and hooked on drugs. They don't make for reliable witnesses."

The danger facing street prostitutes became part of national debate when Diane McInally was murdered in Glasgow in 1991.

The 23-year-old, who was found battered to death in Pollok Park, was the first of eight sex workers to be killed. Gangland enforcer Gary Moore was arrested in connection with her death but the charges were later dropped.

He was one of Scotland's most violent criminals who stood trial for the murders of six members of the Doyle family during the infamous ice cream wars in 1983.

Moore, who died in 2010, was also one of dozens of men quizzed by police investigating Emma Caldwell's death in 2005.

Emma was last seen on April 4 2005 near a women's hostel in the Govanhill area, at around 11pm. Her body was discovered in woods near Roberton, Lanarkshire around a month later by a dog walker.

The anniversary of her death comes amid accusations that police failed to take crimes against sex workers seriously.

Campaigner Anne McIlveen, who was in weekly contact with Emma for years before her death, said the women felt they were not taken seriously by the police.

She said: "The women won't report any attacks to the police, they think it's a waste of time.

"Being in prostitution isn't their fault, it's not a career choice. For some, it's their only option."

Anne, who has helped sex workers in the city for 15 years through her charity Salt and Light, believes the women are often treated as second class citizens.

She added: "One conviction out of eight makes you wonder if it's all about class.

"Everyone should be treated the same, regardless of their class."

John Carnochan, who recently retired as a detective chief superintendent after nearly 40 years, rejected claims that the police had failed to make prostitutes a priority.

He said: "The status of a victim is irrelevant.

"Whether they are rich, poor, black, white, Catholic or Protestant, police are focussed on going after that killer.

"Police would never put less effort into a case because the victim was a prostitute, they would throw the same resources at it as any other murder case.

"I do accept that there are wider attitudes about prostitution and, in general, people don't think that much of prostitutes.

"But in my almost 40 years with the police, I have never seen a senior investigating officer make distinctions between victims. We represent the victims."

Concerns about the investigation into Emma's murder were raised when it was revealed a suspect was interviewed six times by police investigating the murder a decade ago. He admitted previously taking Emma to the remote country track where her body was later found.

Three months later, officers charged four Turkish men with the murder after one of Scotland's most expensive investigation. Within 80 days, the case collapsed.

Last night, the Crown Office said: "Crown Counsel are currently considering whether there are grounds to instruct Police Scotland to reinvestigate the case."

Carnochan echoed our police source's view that prostitute murder investigations were "often very difficult".

He added: "Having sex with a prostitute doesn't necessarily make you a suspect in her murder.

"This man was discounted at the time, and there must have been some reason why he was taken out of the frame."

Police Scotland defended its record. A spokeswoman said: "In the case of Diane McInally, following a significant inquiry a report in relation to the circumstances was submitted to COPFS (Crown Office and Procurator Fiscal Service).

"In the case of Karen McGregor, a male, now deceased, stood trial, however the case was found not proven at court.

"In the case of Leona McGovern, a 51-year-old man stood trial, however was found not guilty at court.

"In the case of Jacqueline Gallagher, a 55-year-old man stood trial, however was found not proven at court

"In the case of Emma Caldwell, a report on the circumstances has previously been forwarded to COPFS and this remains a live unresolved case.

"In the case of Tracey Wyldes, a report has been submitted to COPFS and a male has been arrested in India. Proceedings are now live in relation to this case.

"Following a detailed investigation into the death of Marjorie Roberts, no criminality could be established and a full report on the circumstances was submitted to COPFS."

One of the problems facing detectives working on these cases is that prostitutes come into contact with dozens of complete strangers every night.

They often work in quiet, poorly lit areas without CCTV cameras, and cruel circumstances mean they may be isolated from their family.

Despite these issues, police said each case was "investigated to the highest possible standard with a Detective Superintendent or above allocated as the senior investigating officer.

"Significant resources and officers have been dedicated in an attempt to bring those responsible to justice.

"While these cases remain unresolved they will be the subject of constant review by Police Scotland's Homicide Governance Review Unit to establish if any opportunities exist for further enquiries to be undertaken.

"As we have said previously, we would appeal for anyone who has any information about any of these cases to come forward.

"Any information, regardless of how insignificant it may seem, could prove vital to officers."

Finnie, meanwhile, wants the Lord Advocate to push ahead with a review into the police investigation into Emma's murder.

He said: "Lessons can and must be learned from every inquiry and this is no exception. However, lessons can only be learned if mistakes that have been made are acknowledged."

The police source added: "The public don't always see prostitutes in a sympathetic light. There's no doubt about that. If a little girl is killed, witnesses comes forward in droves and everybody wants to help catch the guy who did it.

"That just doesn't happen when a prostitute is murdered. Anyone involved doesn't want to give evidence. They've got their own secrets."

A Crown Office spokesman added: "Unresolved homicides are never closed. COPFS maintains a database of all cold case homicides and cases to which the Double Jeopardy (Scotland) Act may apply. The Cold Case Unit works closely with Police Scotland to review these cases to ascertain if there are any new evidential developments, including advances in forensic techniques, which would assist in providing a basis for criminal proceedings.

"There is a risk of prejudicing fresh prosecutions by commenting further on individual cases or providing details on how a particular case is being dealt with."