The slaying of 56-year-old man has put neighbors on alert at Arcadia Park, a development of more than 160 single-family homes in East Oakland.

Qingjun Kwin-Jun Sun, a chiropractor and father of two grown children was gunned down near his him where hhe lived with his wife.

"The whole neighborhood is worried," said Charlie Wong, a neighbor. "I'm sure of that. We don't want this to happen again."

Neighbors said they heard two gunshots at around 8:40 p.m. Tuesday. Police are still investigating why Sun was killed, though neighbors suspect robbery.

"I was highly upset," said Sheree Arriola, a neighbor. "I'm friends with his wife. They're really nice people. They did nothing to hurt anybody."

Neighbors said the homes were built about four years ago as part of a project to help beautify East Oakland.

The housing development is located off 880, just blocks from an area known for violence.

Neffertice Lomax is the mother of four and a 911 dispatcher and she said she bought her home because the developer provided safety measures.

"I was in the first-time home buyer's program," Lomax said. "It was a big dream for me to buy a home for my children. My children's father was murdered in our home in San Francisco. This really hits home for me."

Yancy Wysinger, another homeowner, said a constant security presence was around when she first moved to area.

"When we were moving  in, we would see them walk by and wave at them," Wysinger said.

Buut, homeowners said when the developer closed its onsite office earlier this year the security patrols ended.

"Since they left, crime keeps growing," said Kathy Cjhiang, co-captain of the neighborhood watch. "Everything from break-ins to broken cars, even a hit-and-run."

The Homeowners Association said the developer did finally agree to pay for a security gate at one of the developments' three entrances.

However, neighbors said it'll take more than a gate to restore their sense of security.