Police in Birmingham, Mich., had been warned that Merhige could show up there because he had a contact in Michigan. However, Birmingham Police Department dispatcher Frank Russell would not say how that contact was connected to Merhige.
Merhige is also accused of gunning down his pregnant sister's twin and his 79-year-old aunt.
"What led to this incident, we're not quite sure," said Jupiter Police Sgt. Scott Pascarella. "It did not appear there was any altercation prior to this shooting."
Pascarella said Merhige left briefly before returning to the home where 17 relatives had gathered in Jupiter, a small beach town about 90 miles north of Miami. The town is known as a home to celebrities including Michael Jordan and Burt Reynolds.
Pascarella said police first received a 911 call from a neighbor, then another from someone inside the home. The residence, in a well-kept new subdivision with brick-paved driveways, is owned by local TV videojournalist Jim Sitton and his wife. The home was surrounded Friday by yellow crime scene tape and police crime unit vans.
Sitton's daughter Makayla had gone to bed before the rampage, police said.
"God packed a lot of sweetness into that little body," Sitton said. "She's just our life. I don't know how we are ever going to recover."
Sitton told local media that his daughter was supposed to perform in a holiday production of "The Nutcracker." The Florida Classical Ballet Theatre had two shows Friday.
"Makayla was part of our family, and as one of the youngest dancers, she was to be one of Mother Ginger's Children," artistic director Colleen Smith said. "She was a beautiful, dear girl. She was a beam."
The other victims were Merhige's twin sisters, Carla Merhige and Lisa Knight, and an aunt, Raymonde Joseph. Merhige's brother-in-law Patrick Knight was in critical but stable condition at a local hospital. Another man, Clifford Gebara, 52, was grazed by a bullet.
Carla Merhige was a real estate agent in Miami.
"She was a wonderful agent," said Joanna Sherman, a manager at Coldwell Banker Residential real estate. "She was very active in the community and in charities. She was just a genuine, beautiful individual. She always had a smile for everybody."
Neighbors in the Palm Beach County community were shocked as police processed the home.
"Our kids walk the streets by themselves," said Nicole Kemp, 67, who did not know any of the victims. "I thought it was the safest place to live. I guess it doesn't matter, if there's a maniac here."