Three people were killed and at least eight others injured when a gunman on a boat pulled up to a waterfront bar in North Carolina Saturday night and opened fire, officials said.

A suspect Is in custody in relation to the shooting at American Fish Company in Southport, city public information officer ChyAnn Ketchum said in a news release. The extent of the injuries is unknown.

The shooting adds to the growing list of bars, restaurants, shopping centers, schools and other venues in the US generally thought of as safe that have experienced gun violence. There have been at least 320 mass shootings – with at least four people shot, not including the shooter – in the US so far this year, according to the Gun Violence Archive.

The shooting In Southport happened just before 9:30 p.m., when a boat approached the bar and the sole person onboard opened fire, Ketchum said. The shooter then fled toward the nearby Intracoastal Waterway, heading in the direction of the neighboring community of Oak Island.

About half an hour later, a US Coast Guard crew spotted someone matching the suspect’s description loading a boat at a public ramp in Oak Island and detained them, the release said.

The individual is being held by Oak Island police and is expected to be transferred to Southport authorities for questioning, with assistance from the North Carolina State Bureau of Investigation.

A motive has not been determined, but there is “no known further credible threat to the public,” the release said.

Southport is located near the mouth of the Cape Fear River, roughly 30 miles south of Wilmington.

CNN reached out to the Brunswick County Sheriff’s Office, the Coast Guard and American Fish Company for comment. (CNN, excluding headline)