More than six months after gunmen walked into the Bolsa Vietnamese restaurant on Jan. 1 and opened fire, killing three people, police say they've made an arrest. (CBC)

A man has been arrested in connection with a New Year's Day shooting in a Calgary restaurant that left three people dead, including a bystander and two others linked to gangs.

The man was arrested without incident Monday in the city's northwest and is currently in custody, said Calgary police spokesman Kevin Brookwell on Monday afternoon. He said police anticipate the man, whose name has not been released, will be charged with three counts of first-degree murder.

Sanjeev Mann, 22, previously described by police as a known gang member, and Aaron Bendle, 21, called an associate of Mann's, died when three men opened fire in the southeast Bolsa Vietnamese Restaurant on Jan. 1.

The third victim, Keni Su'a, 43, was also eating in the restaurant and tried to escape but was gunned down in the parking lot. Police said the attackers shot and then beat him before he died.

Brookwell said public tips that came from a Crime Stoppers re-enactment filmed last month led to the arrest.

"This [arrest] is significant," he said. "We've all seen the number of shootings and homicides that have happened in the city and the frustration felt ... by the public and the service in not being able to move these investigations forward."

'That's all you pretty much have to hold on to is to hope that justice is done so that his death won't be in vain.'—Lenni Su'a, victim's ex-wife

More than 20 homicides are connected to an ongoing rivalry between two gangs — Fresh Off the Boat (FOB) and the FOB Killers (FK) — since 2002.

"The person that's arrested is known to our gang unit; however, he has not been designated as a gang member through the courts," said Brookwell.

"This investigation isn't closed with the arrest of one person," he added.

Su'a's ex-wife, Lenni Su'a, told CBC News she was shocked but happy to hear news of the arrest.

"That's all you pretty much have to hold on to is to hope that justice is done so that his death won't be in vain, so to speak, because I'm sure these people commit other crimes too," Su'a said from Edmonton where she lives.

"No matter what happens at this point, no matter who's arrested, what charges are laid, what charges hold, what punishment they get, it doesn't bring Keni back. Nothing can."

Su'a said she is trying to reach her ex-husband's large family in Samoa to update them.

The unidentified man is expected to be officially indicted later on Monday.