After a string of almost 200 murders in five years, the Mexican border city of Juarez has become synonymous with fear and death for women.

Frustration with the slow pace of an investigation into the killings has prompted women's rights advocates in Mexico have complained to the country's Interior Ministry.

A group of women surrounded the Interior Ministry building on Wednesday to demand what they called a full investigation.

Raped, tortured, stabbed

Ever since women began flooding into the factories that sprang up five years ago, dozens have been savagely murdered and there appears to be a pattern.

The victims are usually young women working in the assembly plants; their naked bodies have been found raped, tortured, stabbed or strangled in the desert.

According to a group of women's rights advocates, the total has climbed to around 190. Now they say enough is enough.

In a protest outside Mexico's Interior Ministry, the women accuse the authorities of dragging their feet in the investigation and not treating the problem seriously.

The group has called for a special prosecutor and a high powered team of investigators to put an end to the killings.

FBI called in

The key question facing Mexican detectives is just how many people are behind the murders.

They have already convicted a 51-year-old Egyptian man for one and police believe he is responsible for thirteen more.

They have also arrested a number of other suspects, but the deaths have continued.

A team from the American Federal Bureau of Investigation recently conducted its own inquiry and it concluded that the murders were not the work of a lone serial killer, but that many of them were single homicides; possibly by copycat killers.