Cambridge police are searching for the man who assaulted and robbed popular Surrey Street proprietor Louie Chen Tuesday night.

The suspect, who Chen describes as a black male, about six feet tall and 25 years old, entered Louie's Superette--which is next to Mather House--at about 8 p.m. wearing a hooded raincoat and a mask covering part of his face.

After looking around, the man bought a pack of gum and waited until Chen opened the cash register.

Using a wooden pole, he then struck Chen on the side of the head and grabbed money--mostly 10 and 20 dollar bills--from the register, according to Chen.

By the time Chen regained his bearings, the suspect had already run out the door.

Chen suffered only a slight laceration on the right cheek.

A surveillance tape taken from the store's video camera will be reviewed in hopes of identifying the perpetrator, said Frank D. Pasquarello, spokesperson for the Cambridge Police Department (CPD).

The suspect faces charges of armed robbery, and assault and battery with a dangerous weapon.

Louie's Superette is a favorite destination for river House residents, and Chen himself has become a Harvard icon.

According to Chen, the suspect had visited the store several times before, presumably, he said, to scope out the environment.

The area is known for its high rate of street crime, according to Pasquarello.

"Louie's Superette has been the scene of other crimes before," he said.

Chen confirmed that he has been robbed several times.

"Ten years ago, somebody robbed the store with a gun," he said. "My brother and I were working at the time, and he didn't really speak English, so he couldn't understand what was going on. I had to tell him in Chinese, 'We're being robbed!'"

After another incident on Halloween, when a group of kids descended on the store looking for beer, Chen was left with a black eye.

Chen said Tuesday's robbery raises concerns that he hopes the police will soon address.

"I pay a lot of taxes," Chen said. "I think it's wrong that [crimes] happen here so often."

Pasquarello said he agrees that crime in the area is a problem, but he doesn't perceive the rate as being unusually high.

He cited a CPD crime analysis that showed that total crime in Cambridge has declined in the first two quarters of this year.

Reported robberies are down 18 percent--and down 50 percent in the neighborhood around the store, according to the CPD report.

"It's an area with a lot of foot traffic, and we've made a lot of arrests there before," Pasquarello said. "But it's no different than any other part of Cambridge. All in all, it's a relatively safe area."