05/03/2012 at 01:15 PM EDT
Junior Seau was apparently smiling, charming and seemingly happy at a charity event Monday, possibly his last public appearances before his death Wednesday
from a self-inflicted gunshot wound.
A photo from the 18th Annual 911 for Kids Celebrity ProAm Classic
, held at the St. Regis Monarch Beach Golf Links in Dana Point, Calif., shows Seau in a black polo shirt and cap, smiling and apparently relaxed with Karma Tequila co-founder Gary Eisenberger and an unidentified woman.
Event reps say the NFL star was jovial and joked around with other guests as he sipped tequila.
Seau, 43, was deeply involved in charity work, having donated nearly $4 million for services and scholarships to children and young adults. 911 for Kids
is an organization dedicated to teaching children about the seriousness of calling 911 and how to properly communicate with emergency operators.
As his friends and family grieve
his death, police are investigating it as a suicide.