Updated

WEST PALM BEACH, Fla. -- Authorities searched the home of parents accused of abusing twin 10-year-olds -- a girl who was found dead in the back of a pickup truck and a boy who was critically injured in the front seat after police said his father doused him with a chemical.

A chemical was also poured on the girl, Nubia, and it was difficult to determine whether she had been abused before her death, according to officials who spoke on condition of anonymity because they were not authorized to talk about the case publicly. It's not clear whether the chemical was poured on the girl before or after her death.

The father, Jorge Barahona, is charged with attempted first-degree murder and aggravated child abuse with a weapon for allegedly dousing Victor with chemicals. He told police he loaded his dead daughter into the truck and got into the pickup with his son, Victor, and planned to kill himself. The boy was found convulsing in seizures, overcome by the toxins. The father was nearby on the ground, unresponsive.

Barahona pleaded not guilty Friday. He is being held without bail and ordered not to have contact with Victor or other children.

Meanwhile, police were also interviewing his wife, Carmen Barahona. Child welfare officials said she repeatedly covered for her husband in the days before the twins were found in a truck. Law enforcement officials said the truck was so toxic several rescue workers were sickened and had to be treated.

The Department of Children and Family said they expect charges will be filed against the mother. West Palm Beach Police Capt. Mary Olsen said they're reviewing evidence, and authorities searched the couple's Miami home late Thursday night, but she wouldn't give details.

Child welfare officials have said the couple tied the twins' hands and feet and locked them in the bathroom as punishment. The couple, who adopted the twins out of foster care in 2008, have been the subject of three abuse investigations in the past few years.

A public defender for Barahona, James Snowden, did not return calls seeking comment and. A telephone message could not be left for Carmen Barahona's attorney, Grissel Picot, and an e-mail seeking comment was not immediately returned.