We may never know exactly what happened five years ago at Doyle’s Bayou Park near Zachary when Jessica Johnson Palmer and her 3-year-old son were murdered, and two of her young children — one whose throat was slit — were left for dead overnight in the BREC park.

We may never know why Jessica Palmer suffered 21 knife wounds to her neck and was nearly decapitated, why little Juan Palmer Jr. suffered six knife wounds to his neck that killed him, or why 4-year-old Paige Johnson — whose throat was cut from one side to the other — and 6-month-old Robbyn Palmer were left for dead.

We may never know whether it was Dominique Dantoni Smith, who is Paige’s father, or Trendall Lashel Matthews, who is Jessica Palmer’s cousin and was Smith’s girlfriend, or both Matthews and Smith, who cut the 23-year-old Palmer.

We may never know whether it was Smith or Matthews who left a blunt-force wound on Palmer’s head that a doctor said was sufficient to knock her out.

We may never know whether it was Smith, Matthews, or both, who cut little Juan. And we may never know whether it was Smith, Matthews, or both, who cut Paige’s neck.

What we do know is that an East Baton Rouge Parish jury on March 25 unanimously rejected Smith’s contention he was not at Doyle’s Bayou Park on Port Hudson-Pride Road on May 4, 2008, and had absolutely nothing to do with the crimes.

What we do know is Smith, 31, of Wilson in East Feliciana Parish, will spend the rest of his life in prison — perhaps at the Louisiana State Penitentiary at Angola, where he was training to be a prison guard at the time of the park attack. He will be sentenced May 24.

And what we do know is Matthews, 25, of Jackson, also in East Feliciana Parish, is spending the rest of her life at the Louisiana Correctional Institute for Women in St. Gabriel after pleading guilty in 2011 to two counts of first-degree murder and two counts of attempted first-degree murder in exchange for life terms.

She had faced a possible death sentence.

Smith, who was convicted of those same charges, was offered the same deal but rejected it. Then, in early March shortly before jury selection began in Smith’s case, the East Baton Rouge Parish District Attorney’s Office withdrew its notice of intent to seek the death penalty against Smith.

Prosecutors cited concerns raised by Paige’s family over the child’s welfare.

The trial, which included five days of jury selection and seven days of testimony, was highlighted by a jury tour of the crime scene and testimony from Smith, Matthews and Paige, who is now 9 and living with her grandmother.

Prosecutor Darwin Miller argued to the jury it was inconsequential who was more evil, Smith or Matthews.

“They’re both disgusting. Hate them both,” he said.

Even though the state did not need to prove a motive, Miller suggested one for the jury: a paternity test Smith was scheduled to undergo May 16, 2008, just 12 days before the park became what Miller called “a killing field” for Smith and Matthews. Jessica Palmer had filed the petition against Smith in late 2006.

At the time of the attack, Smith had three children with his wife, and three more with three other women, one of them Jessica Palmer. DNA evidence introduced at the trial confirmed Smith is Paige’s biological father.

Smith’s lead attorney, Daryl Gold, characterized Matthews as a pathological liar and told the jury he believes Paige was “coached” by her grandmother and others.

Miller was quick to defend Paige, arguing, “That little girl had no reason to tell you anything other than the truth.”

Joe Gyan Jr. covers courts for The Advocate. He can be reached at jgyan@theadvocate.com.