JACKSONVILLE, Fla. -

Police say cellphone records were the biggest piece of evidence that led to the arrest of a mother accused of shooting and killing her 24-year-old daughter.

At a news conference Monday to discuss the arrest of 53-year-old Silvana Catignani, homicide detectives also said she couldn't account for where she was for about 45 minutes that December day Nicole Catignani (pictured below) was shot in the head.
"From day one, the mother was a suspect, along with a few others," said Lt. Rob Schoonover, of the Jacksonville Sheriff's Office.

Police said the mother and daughter got involved in an argument, and they said Silvana shot Nicole once in the head through a pillow.

Detectives said instead of calling 911, Silvana left the house to get rid of the gun.

Police said inconsistencies in her story and cellphone records led to her arrest. They said the records reveal she wasn't where she claimed to be.

Police said Silvana told them she threw away her pistol two months before the shooting, but two people told police they saw her with the gun the night before.

"When they brought her in, she finally did confess to -- now she is claiming it's accidental," Schoonover said. "We do not believe it was accidental. It was a murder."

Silvana and her brother, John Demeo, tell a different story.

Demeo said his sister was on a drug run for her daughter, and when she came back with no prescription pills, Demeo said Nicole flipped out.

"I don't want the people to think, 'Oh, we just got a woman that just shoots her child and that's it. That's not the case," Demeo said.

He said Nicole grabbed a gun and went after her mom.

"Ran around, got down the hall, into the bedroom, which happened to be her (Nicole's) bedroom. I believe it was," Demeo said. "And when she came inside the doorway, that's when Silvana, the mother, was able to grab her and they struggled, and the gun went off and she dropped."

Silvana was also arrested in March for possession and sale of prescription drugs.

Police said the mother and daughter were running a pill operation out of their Mandarin home.