Free vodka samples, grilled chicken and hamburgers marked the reopening Thursday of Port City Liquors in North Charleston, a festive occasion with an undercurrent of tragedy and mystery because of the unsolved murder of the previous owner.

“There was a sadness here,” said Mayor Keith Summey. “Part of the sadness is we have never been able to solve the mystery.”

In April, Matthew Renken was fatally shot in the head while working in the store after business hours. Police found a disheveled scene of broken liquor bottles, an unhooked telephone, a handgun and an unlocked back door.

“It’s been really a quagmire to figure out what happened. It’s one of those freakish things,” Summey said.

Because of the circumstances, “Somebody had to know somebody. It may be a shocker to all of us,” Summey said.

Summey noted that there had been no major incidents in the shopping center where the liquor store is located since the shooting death of Renken. Police checking businesses on routine patrol will keep an eye on the liquor store, he said.

A poster in a store window offered an $11,000 reward. “Who killed Matthew Renken?” it said. Tipsters can call Crime Stoppers at 554-1111.

“It’s not in a dead file,” Summey said. “It’s in a file that’s moving forward.”

The new owners are cousins Preksha and Gopal Patel. The store opened quietly in October, followed by the grand opening Thursday.

“It’s something I always wanted to do. After the tragedy that happened here, I wanted to bring it back alive. We kept the same name in honor of the previous owner,” said Preksha Patel.

She said the cousins try to stay safe in their store operations.

“Business could be better. A lot of people are still learning that it is open,” she said.

The store is located at 4400 Dorchester Road.

Ed Pendarvis, whose firm sold the business to the Patels, said the location is safe.

“Matthew was a nice young man and he had a good business here. It’s a good neighborhood store,” Pendarvis said.

He noted that the crime happened late on a Sunday night when the store was closed and Renken was inside straightening up.

“It wasn’t a break-in robbery,” he said.

Renken purchased the liquor store in September 2011. Having owned the downtown Gateway Inn and an event-planning business, Renken built a reputation in the hospitality industry.

Despite its 48 years in business, the North Charleston store had suffered in recent years before Renken bought it. Inventory was depleted and customers slacked off.

Renken, 39, changed that. He attracted new customers, one of whom often brought him lunch. He missed his 20-year reunion at Bishop England High School because of his diligence.

North Charleston Deputy Police Chief Scott Deckard said police are still actively investigating Renken’s death, but no suspects have been identified.

Deckard said investigators continue to speak with people to develop leads, and they are waiting on results of some evidence that is being analyzed.

Police were hopeful that new leads would surface when they revealed in May that Renken’s gold Rolex watch was missing when his body was found. So far, they have received no reported sightings of the watch, Deckard said.

The absence of the watch would suggest that robbery played a role in the killing, but Deckard said no firm motive has been established.

Glenn Smith contributed to this report.