The elite audience at a Nigerian film premiere cheered the final scene - a robber being "necklaced" or burned alive by vigilantes with a tire round his chest.

And among those who endorsed the do-it-yourself answer to violent urban crime was the police chief of black Africa's most populous country."Vigilante," a chilling film based on real life, was produced by two young brothers and recently had its premiere in Lagos.

It tells how a middle-class Lagos neighborhood is terrorized by armed robbers and looks in vain for police protection. Eventually the residents fight back and form a vigilante brigade to defend their lives and property.

In a speech at the end of the 106-minute film, national police chief Mohammed Gambo signaled high-level backing for vigilante groups like those in the film that have sprung up in Lagos and other major cities.

"The ultimate responsibility for the defense of family and property rests squarely on the people themselves," he said.

Film producer Afolabi Adesanya and his brother, Adediji, the director, say the crime crisis depicted in "Vigilante" is backed up by the fact that two out of every five Nigerian city dwellers have had a brush with robbers.

For many years, convicted armed robbers have been executed by firing squad - 16 of them in Lagos on one recent Saturday - but the security situation has scarcely improved.

On most days, newspapers carry obituaries of citizens murdered by gangsters stealing their cars or raiding their homes.