(CNN) -- The father of a 6-year-old girl, one of four relatives who police say were killed by another family member on Thanksgiving Day, said it was "unbelievable" how a tip from a television viewer brought about the arrest of the suspect.
"Before the show even came on, Paul was being surrounded by the people behind me," Jim Sitton said Tuesday in Jupiter, Florida, standing in front of police officers.
Paul M. Merhige is accused of fatally shooting his twin sisters, Sitton's 6-year-old daughter Makayla -- Merhige's cousin -- and a 79-year-old aunt at a family home in Jupiter, Florida, on November 26.
One of his sisters was pregnant. Police said Merhige also wounded two other family members during the shooting rampage.
A viewer of the television show "America's Most Wanted" recognized descriptions of Merhige and his car and called police. Officers responded to the tip late Saturday, surrounding a small motel in the Florida Keys and taking Merhige into custody.
Sitton said the tip came in from a promotional announcement before the show aired, not the show itself. The couple at the hotel who called police went outside and lifted a tarp to look at Merhige's license plate and verify it was the vehicle sought, he said.
"So many people don't make the call, and they made the call," Sitton said. "The monster's in a cage and now we can get out of protective mode and begin the process of healing."
He said he's not "jumping for joy" at the arrest, "because our daughter's room is still empty. There's dresses and shoes in there that will never be worn again."
While the arrest won't bring his daughter back, he said, "this is the first step toward justice. ... If there's anyone that deserves the death penalty, it would be someone who would go and execute my 6-year-old daughter while she is sleeping in her bed."
Merhige made a first appearance in court on Sunday. He is charged with four counts of premeditated murder and attempted first-degree murder. His next court appearance is February 1. He is being held without bond at the Palm Beach County jail.
"America's Most Wanted" host John Walsh told reporters he got involved in the case after his wife called him and told him she had been seeing news reports on it, and pushed him to air information on the suspect, who had been at large since Thanksgiving.
"I really believed that the public would make the difference," said Walsh, who met with the Sittons on Tuesday, according to the AMW Web site.
He said Sitton's home had been under police protection and Sitton had patrolled his home nights with a shotgun since the incident.
Walsh also said Merhige deserves the death penalty. "He killed four people, including a pregnant woman. He needs to pay."
He cautioned the media to be gentle with the Sittons, saying, "these are decent, wonderful, good people that are getting ready to go through hell."
Walsh has been involved in assisting crime victims since his 6-year-old son, Adam, was abducted and killed in 1981.
According to its Web site, "America's Most Wanted" has helped find more than 1,050 fugitives and bring home more than 50 missing children in its 22 years on the air.