One of the victims, a well-known businessman in the community, did not survive.
It's the first murder in Westport in 25 years.
Police are operating on the theory that a lone gunman targeted the jewelry store, which has been in business since 1981. The incident happened around 10 p.m.
Yekutiel Zeevi, 59, a native of Israel who was known to his friend as QT, was gunned down and pronounced dead at the hospital. His associate, identified as Ronen Konfino, remains in critical condition. Police think the high-end jewelry store, YZ Jewelers, was targeted.
Police say the gunman was partially caught on a hallway surveillance camera. Authorities are hoping someone recognizes him.
The suspect is described as a white man in his early 40s, 5'10"-6', medium build with thin or short hair (salt and pepper). He was wearing black frame glasses, a blue jacket with white stripe, blue jeans and cowboy boots
They believe he had an appointment at YZ Jewelers, located in a suite of offices in Westport's Compo Shopping Center, the previous day and returned with robbery as his motive. It is unclear if anything was taken.
Friends say Zeevi took pride in his custom designs, traveling to diamond mines in South Africa and cutting and mounting the stones himself.
The store reportedly had a very elaborate security system that requires customers to get buzzed in twice. The security is so tight that responding officers apparently had a hard time getting in to render aid to the victims. Investigators are trying to figure out how the man was able to make it inside with the gun.
Anyone with information is asked to call the Westport Police Department Detective Bureau at 203-341-6080.