But most criminals are not caught

Professor James Mullins from University of Washington was mugged by seven men outside his hotel in Durban, where he was due to release his findings at South African first-ever conference on Aids.

Professor Mullins has offered a reward of 7,000 rands ($940) for the return of his laptop, SABC says.

A study suggests that police are unlikely to find those responsible, as less than 10% of South Africa's violent criminals are convicted.

VIOLENT CRIMES 75%: Unsolved after two years 4%: Trial continuing 10%: Cases withdrawn in court 6%: Convictions 5%: Suspects acquitted Source: South African Law Commission

"Crime pays," concludes the author of the report for the South African Law Commission, advocate Ron Paschke.

Mr Paschke tracked some 15,000 violent crimes (murder, rape and robbery with aggravating circumstances) and fraud reported to the police in 1998 for two years.

"Violent criminals get away with their crimes. For every 100 violent crimes reported to the police, perpetrators in only six cases had been convicted after more than two years," says the report.

Vigilantes

Mr Paschke told BBC News Online that this was an incentive for people to commit crimes.

"People also lose faith in the justice system and resort to vigilant actions," he said.

He said that he could not say whether the situation had changed since 1998 but said he was not aware of any studies that have been conducted more recently.

Police spokesman Senior Superintendent Lazarus Tlomatsana said he was not able to comment on the report.

The study says that Johannesburg has the lowest conviction rates, with 76% of murders and 93% of violent robberies going unsolved.

Mr Paschke pointed to a number of factors:

• Poorly trained and overworked detectives and prosecutors;
• High levels of illiteracy and low morale in the police service;
• Witnesses often fail to co-operate with the police.

About half of murders are solved in the US and England and Wales.