A brick-wielding thief attacked a man in his own residential building yesterday, robbing him of 37,000 yuan (US$4,542), police said.

The victim, surnamed Wu, was returning home in Chuansha area of the Pudong New Area from the bank about 1:40pm, carrying money in his pockets.

This was the second attack in the city within a week when the victim was returning home after withdrawing cash.

Wu suffered head injuries and required stitches. He was in stable condition last night.

As he returned to his home building on Xinde Road and went to the fourth floor, Wu was struck on the head from behind with a brick, according to his wife, surnamed Lu.

The robber threatened Wu, who screamed out. "You will be dead if you yell again," the attacker said, Lu told local TV news. The man pushed Wu down to the third floor and knocked him out using a flowerpot, Lu added.

When Wu regained consciousness, he realized he had been robbed and staggered up to his home on the fifth floor for help.

Police have established a special squad to track down Wu's assailant, who is described as in his 30s, square-faced and about 170cm tall.

Last Tuesday, a man was hit by a hammer and robbed of 50,000 yuan after withdrawing money in Putuo District. A suspect was detained last Friday.

City police are reminding people to ensure they are not followed from banks.

Meanwhile, a have-a-go hero is recovering after a gang of thieves battered him after he tried to stop them robbing pedestrians in Putuo District.

Guan Guoliang, suffered head injuries in the attack on Saturday, but has since been released from hospital and was resting at home yesterday.

"I am glad that my son did the right thing," Guan's father, Guan Qunzhang said.