The reward now stands at $25,000 for any information that leads to an arrest.
Investigators say at least two gunmen carried out the attack at a home in Goshen on January 17.
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Many of the victims were family members, including a teen mother and her 10-month-old baby boy.
The sheriff's office now expects to provide an update on the investigation next Monday.
RELATED: Shooter stood over teen mom, baby before killing them at Goshen home, sheriff says
Sheriff Mike Boudreaux says the shooting appears to be tied to gangs and possibly drugs.