ROYAL PALM BEACH — In a Publix filled with lunchtime shoppers, a man Thursday walked into the produce section, fatally shot a woman and her young grandson, and then turned the gun on himself, the Palm Beach County Sheriff’s Office said.

What we know about Royal Palm Beach shopping plaza shooting.

Investigators believe the woman was shopping with her grandson, but they are still trying to determine her relationship to the gunman, said sheriff's spokeswoman Teri Barbera.

The murderous attack at the store in The Crossroads shopping plaza at Royal Palm Beach and Okeechobee boulevards sent panicked shoppers and workers scurrying for cover, witnesses said.

"I heard, 'They're shooting!' A woman Publix worker said, 'Run.

I can’t believe this crazy thing happened,” said Tracy Greene, a regular at the shopping center.

“I’ve been here for 20 years, and I can’t believe this is happening,” agreed Tracey Cohron, a Royal Palm Beach resident who often shops at the Publix.

Oahtee Moody, a Royal Palm Beach resident who lives across the street from the center, said the shooting was a tragic sign of the times.

Detectives are investigating a shooting that took place INSIDE Publix in RPB. Upon arrival deputies located three individuals deceased from gunshot wounds, one adult male, one adult female and one child. The shooter is one of the deceased.

Several PBSO vehicles are blocking the entrances of the Publix in Crossroads shopping center on Okeechobee Boulevard and Royal Palm Beach

In a tweet, to alert the public of the Publix shooting in Royal Palm Beach, the sheriff's office sought to calm people’s worst fears

"Detectives are investigating a shooting that took place INSIDE Publix in RPB