PROVIDENCE — A weekend fire at an alleged illegal “sip joint” in South Providence was arson, set with a liquid accelerant, city Fire Marshal Anthony DiGiulio said yesterday.

A sip joint, according to the police, is a place where a bar is set up — usually a house — for the illegal sale of alcoholic beverages at times when bars are closed.

One man was shot to death and another man was shot and wounded outside the sip joint, at 76 Baxter St., on Nov. 4. There is an outstanding arrest warrant charging Dennys Cabrera, 24, of Providence, with murder. He remains at large.

Late Saturday afternoon, nearly three weeks after the killing, a fire heavily damaged the 1½-story building. Deputy Assistant Fire Chief J. Curtis Varone said firefighters encountered heavy fire on the first and second floors of the unoccupied structure.

Flames destroyed the second floor and heavily damaged the roof, and there was fire, smoke and water damage on the first floor, Varone said yesterday.

Firefighters found a partially melted plastic fuel container on a stairway leading to the second floor.

“There was evidence that some type of accelerant was spilled in the stairway leading up to the second floor, and a container, a gasoline-type container, was found on the scene with what appeared to be accelerant still in it,” DiGiulio said.

Liquid samples and pieces of wood from the stairway were submitted to the University of Rhode Island Crime Lab for tests to determine the nature of the accelerant, and the container was turned over to the Police Department Bureau of Criminal Identification in the hope that an fingerprint or fingerprints could be lifted, according to DiGiulio.

Asked if there is a connection between the homicide and the fire, the fire marshal replied, “We have no idea, but because of that homicide, our investigators are working with police detectives, sharing information …”

Police Lt. Thomas A. Verdi, commander of a unit that has investigated the alleged sip joint, referred questions to his superior officer, Maj. Stephen Campbell, commander of the Investigative Division. Campbell could not be reached for comment yesterday.

Shortly after 2 a.m. Nov. 4, Nairobi Acosta, 20, of Providence, and Claudio Nieves, 19, of Pawtucket, who had been inside the sip joint, went outside to the driveway to smoke and were shot, the police said. Acosta fell dead in the driveway and Nieves, shot once in the shoulder, climbed over a chainlink fence behind the house and escaped his assailant.

The police said later that there had been an undercover investigation of the sip joint for the week before the shootings. But no officers were present at the time of the shootings.

When firefighters went inside Saturday, according to Varone, they found a house converted to a tavern.

“There was a living room and there was a bar set up where a kitchen used to be on the first floor,” he said. “It did not look like it was open for business or had been open for business in the past few weeks.”

DiGiulio said the Fire Department has not confirmed the identity of the owner of the property.

gsmith@projo.com