RIO DE JANEIRO (AFP) - A Rio policewoman made a gruesome discovery outside her home on Tuesday: a backpack containing the head of her husband who had been kidnapped overnight, police said.

The victim, a 35-year-old shopkeeper and former footballer, was abducted outside his shop near Rio's Minha Deusa shantytown and whisked away in his own car by unidentified assailants. Police said the policewoman ventured outside her home early on Tuesday and recognised her husband's backpack.

"She opened the backpack and inside was the head," one officer added.

According to the G1 news website, the eyes and the tongue of the victim had been plucked out, and police believe a local drug gang may be responsible. The policewoman belongs to one of the city's Police Pacification Units (UPPS) set up in 2008 to occupy and impose order in favelas.

The Brazilian authorities are battling to reassert control in lawless areas ahead of next year's World Cup, after evicting the drug traffickers who had previously held sway. It was the second bloody incident in a few days in the area, where seven people were gunned down last Thursday in what police also believe may have been gang-related violence.

Despite the deployment of the UPPs, violence often flares in the favelas and is sometimes blamed on police. In Rocinha, Rio's biggest favela, 25 members of the local UPP were recently jailed for roles in the torture and killing of construction worker Amarildo de Souza in July and for trying to blame traffickers.