LAPLACE — LaPlace cousins were killed early Monday when they and a third person were shot while exiting a vehicle in the 400 block of State Street in LaPlace.

Travis Gregoire, 23, of LaPlace and Sierra Gregoire, 18, of LaPlace died Monday after a barrage of gunfire erupted at approximately 1:50 a.m. Monday.

St. John the Baptist Parish Sheriff Mike Tregre said a third victim, a 23-year-old man, was in stable condition Tuesday morning at University Medical Center in New Orleans.

“We have reason to believe that the victims had just arrived in a vehicle of their own and were exiting the vehicle, and that’s when this white pick up truck drove up and opened fire,” Tregre said.

Deputies responded at 1:52 a.m. Monday to the 400 block of State Street following the shooting report.

Tregre said the white truck believed to be involved in the shooting was discovered Tuesday morning after it was set on fire in Reserve.

“Once the truck cools off, we are going to examine it for any physical evidence,” Tregre said Tuesday morning before press time. “We are going to tow it to our office and go through a thorough examination of the remains of the truck.”

Authorities said it is unknown how many occupants were in the truck.

“We have various numbers, but we don’t have anything concrete or 100 percent yet,” Tregre said. “We have some suspicion and some street talk and some rumors, but we will take that. It’s better than no calls at all.”

Authorities are asking residents to call in with any available information.

Tregre said he doesn’t want to release information on how many gunshots were fired and what types of weapons may have been involved because he doesn’t want to jeopardize the investigation.

During a press conference Monday afternoon in front of the Sheriff’s Office headquarters in LaPlace, Tregre said detectives are making progress in their investigation.

“This was a very brutal and vicious attack,” he said. “I cannot stand here and tell you if it was one gun or multiple, and I can’t stand here telling you if it was one weapon or multiple. I’m not going to do anything to jeopardize this case.”

Tregre said detectives are working to establish a motive, adding there is nothing to suggest gang violence. He said the two people killed were cousins and autopsies are being performed.

Tregre’s office previously announced victim Sierra Gregoire was issued a misdemeanor summonses for simple battery Aug. 31 for her involvement in a highly publicized assault that took place at an Airline Highway fast food restaurant in LaPlace.

Tregre said detectives are looking into the possibility the cases are related, but added “there are no ties to that incident at this time.” The sheriff also said “no direct link” has been established between Monday’s violence and the parish’s first homicide, which took place Sept. 16 in Garyville.

The deaths of Travis Gregoire and Sierra Gregoire represent the parish’s second and third killings of 2015.

Anyone with information regarding the shooting is asked to call the Sheriff’s Office TIPS line at 985-359-TIPS or Crimestoppers at 504-822-1111. Those that call Crimestoppers do not have to testify and may qualify for a cash reward.

Residents can also submit tips at stjohnsheriff.org/submitatip.php.

— By Raquel Derganz Baker