A Quebec retiree was among three people killed Thursday evening when a man opened fire in a Deerfield Beach, Fla., camper park.

Police say the gunman entered the RV park around 6:30 p.m. and shot a man outside of a camper.

Witness Norman Robert said he heard screams and gunshots and saw the Quebec man standing outside the RV.

"He walked a few steps and then he turned around and said in French, 'Call 911, I've been shot.'"

Ovila Plante, 76, of La Tuque, Que., was pronounced dead on the scene. Residents had initially said he was the gunman's ex-father-in-law, but police said the relationship between the two wasn't clear.

The gunman barricaded himself inside the RV with his wife, two sons and another woman. The children's mother managed to flee and a seven-hour standoff ensued.

Eyewitness Robert Guertin told QMI Agency that "(a) child tried to leave but he grabbed him and pulled him back inside."

Guertin said the shooter yelled out a chilling message to police officers who tried to approach the RV.

"He said, 'Don't come close or I'll shoot them all.'"

Police said the gunman shot his nine-year-old son to death and also shot a woman and his seven-year-old son before turning the gun on himself.

A SWAT team entered the camper around 1:30 a.m. Friday to find the dead and injured. The wounded woman and child were rushed to hospital in critical condition.

The gunman was identified as William De Jesus, 41, of Port Orange, Fla.

The shooting took place in the Highland Woods R.V. Park, an area that's popular among Canadian snowbirds.