Police in North China's Tianjin municipality said Sunday that electric short circuit caused the mall fire which left 10 people dead and 16 others injured on June 30.

Investigators found that the power line short circuit of an air conditioner located in a warehouse on the first floor in Laide Shopping Mall kindled inflammable stuff, triggering the fire, official sources said.

Of the 16 injured people, nine have been discharged from hospital, local authorities said.

Police penalized a few netizens who spread rumors on more deaths in the fire and fabricated quotes of witnesses on the Internet, the police said.

The police said the netizens had admitted the offense, without specifying what penalties they might face.

The fire engulfed the five-story mall in Jixian county in June 30 afternoon, killing eight mall workers, a home textiles saleswoman and a customer.