A convoy of heavily armed gunmen launched a bold attack on a senior Mexican state prosecutor, then continued to toss grenades and shoot at officers in a midnight chase through the Gulf state's capital.

Assistant Tabasco state Attorney General Alex Alvarez was unhurt inside his armored vehicle, but a bystander was killed and 13 other people were injured, including six officers, police said Thursday.

Alvarez said his four bodyguards were seriously injured in the attack around midnight Wednesday in Villahermosa, a city of about 330,000 people.

The attackers fired gunshots and hurled grenades from windows as they raced past malls, movie theaters and homes. Police said they lost the gunmen after a 3-mile (5-kilometer) chase, but later found four of their abandoned, bloodstained vehicles.

Officers mistakenly shot and killed a man who was sitting in his vehicle, believing he was involved, Alvarez said.

"It's unfortunate that a civilian has died. Something happened and we're going to investigate," he said.

Organized crime gangs have been launching increasingly brazen attacks on police and soldiers across Mexico, and Tabasco, which borders Guatemala, is a conduit for U.S.-bound cocaine.

Gunmen killed a police detective, his wife, two children and four others in their home on the outskirts of Villahermosa earlier this month. In February, assailants killed a state police officer and 10 members of his family, including five children.

More than 10,750 people have been killed in drug violence since President Felipe Calderon launched his national crackdown on organized crime, sending more than 45,000 troops to drug hot spots.