Prosecutors today described a horrific scene inside a Skokie home where a man killed his 18-year-old daughter and 2-year-old granddaughter, with the child hitting him with a toy to make him stop.

As his daughter Cynthia lay dying on the living floor, Miguel Renteria grabbed a second knife and turned on his granddaughter Jeiloni, stabbing her 10 times, authorities said.

“While the knife was in her little heart, he made the sign of the cross,” Cook County Assistant State’s Atty. Diann Sheridan said, quoting from his confession.

His hands covered with blood, Renteria then called 911 and told police he had just killed his daughter and granddaughter, authorities said.

Sheridan said the words brutal and heinous “only minimally describe the horror he inflicted on members of his family.”

Renteria -- who relatives say has suffered from mental illness for years -- had called his daughter earlier Wednesday and said he had signed her up for a Bally’s health club membership and would pick her up at her home in Chicago, Sheridan said.

But first, he picked up a knife and put it by a lamp in his living room, she said. Renteria drove into Chicago and picked up his daughter and Jeiloni and returned home, Sheridan said.

When he got inside, the child began playing with toys as Renteria picked up the knife and stabbed his daughter in the chest, Sheridan said. The knife broke, and the two struggled and fell to the floor.

Renteria then pushed his elbow into his daughter’s throat until she stopped moving, Sheridan said.

The 2-year-old was screaming and crying and hit Renteria with one of her toys, Sheridan said. That's when he got a second knife and stabbed his granddaughter.

When police arrived shortly after noon Wednesday, the mother and her child were lying next to each other in the living room of the home in the 4600 block of Main Street in Skokie, Sheridan said. Renteria was taken into custody and made a confession, Sheridan said.

Cynthia Renteria died of strangulation and a stab wound to the chest, according to the Cook County medical examiner's office. Her child died of stab wounds.

Renteria, his face scratched, showed no emotion as he stood in court this afternoon while Sheridan recounted the gruesome details. Surrounded by deputies, he calmly answered, "Yes," when asked if his name was Miguel Renteria.

Judge Lauren Gottainer-Edidin denied him bail.

Renteria's father, Octavio Renteria, said his son is mentally ill and prone to fits of violence.

"My son Miguel is sick, I don't know if his sickness is causing these things," Octavio Renteria said this afternoon.

"He didn't want to be with people," Octavio Renteria said. "If there was a family gathering, he would hang out alone."

Octavio Renteria said his son has suffered from mental illness for at least 10 years and it has caused him to act aggressively and erratically. He said his son has been arrested several times over the years. Cook County court records show he has been charged with battery and assault, among other crimes.

Octavio Renteria said at first he thought his son was involved with drugs or was hanging out with the wrong people on the streets of Chicago. Then, he said, Miguel was diagnosed with mental illness and saw several doctors.

"He would get into accidents and sometimes just leave the car wherever," the father said. "One time he went to Cook County Jail and another time he got into an accident at the airport. "You knew he wasn't doing well."

"I feel so bad for them," he said of his granddaughter and great-granddaughter. "I don't feel bad for my son as much as I do for those poor creatures who had nothing to do with this. The girls had no blame for what happened."

Octavio Renteria said he and his son last spoke several months ago when his son called to check up on him and see how he was doing.

Miguel grew up on the North Side of Chicago and worked as a pizza delivery driver.

According to Cook County records, Renteria has been arrested about 16 times since 1990 when he was convicted of unlawful use of a weapon and was sentenced to court supervision. In 1993, he was convicted of aggravated battery and was given a 5-year prison sentence, according to records.

Carlos Sadovi is a Tribune reporter, Brian Cox is a freelance reporter.

chicagobreaking@tribune.com