Prosecution testimony begins in trial of man accused of killing his baby on Highway 74

INDIO, Calif. (KESQ) - Prosecution testimony got underway Wednesday in the trial of a felon accused of killing his year-old daughter and stabbing his pregnant wife after turning irate during a child custody exchange in Indian Wells.

Adam Slater, 53, of Palm Desert allegedly killed baby Madalyn in 2020 during an act of rage that included a severe assault on his estranged wife and knifing a good Samaritan, culminating in a rollover crash in the hills alongside Highway 74 near Pinyon Pines.

Slater is charged with first-degree murder, attempted murder, assault on a child resulting in great bodily injury, assault with a deadly weapon, child concealing, resisting arrest, a special circumstance allegation of killing in the course of a kidnapping and sentence-enhancing allegations of using a deadly weapon -- a knife -- in the commission of a felony and inflicting great bodily injury.

The prosecution and defense delivered opening statements Wednesday morning at the Larson Justice Center in Indio, after which prosecutors called three witnesses before Riverside County Superior Court Judge Otis Sterling adjourned proceedings for the day. Testimony will resume Thursday morning.

Slater is being held without bail at the Benoit Detention Center.

According to a trial brief filed by the District Attorney's Office, in early 2020, the defendant and his wife, whose name was not disclosed, separated, but the two shared custody of Madalyn. After keeping the year-old girl with him for an unspecified number of days, he and his wife arranged to meet outside the Southwest Church on Washington Street in Indian Wells, where the woman was to retrieve the tot.

However, after taking the girl from Slater and placing her in her vehicle, the defendant "suddenly attacked" the pregnant victim without explanation, the brief alleged.

"He pushed her into her car, and she fell to the floorboard,'' the narrative stated. "The defendant stabbed her under her chin and abdomen with a serrated knife and punched her face. She screamed, and he covered her mouth with his hands. Good Samaritans began honking their horn to make noise to interrupt the assault, and the defendant grabbed Madalyn and placed her in his car and sped away."

With the knife still protruding from her stomach, the victim called 911 to report the assault and abduction, according to the brief.   

While he accelerated away from the location westbound, Slater called his roommate and told her he intended to commit suicide, then hung up, according to court papers.

Slater steered his car onto two-lane Highway 74, heading into the steep hills that mark the start of the San Bernardino National Forest, going in the direction of Pinyon Pines, west of Palm Desert. The defendant allegedly stomped his accelerator and drove off a cliff into a ravine, where the vehicle overturned, prosecutors said.  

A motorist witnessed the crash and immediately stopped on the shoulder of the highway, making his way quickly to the bottom of the embankment, intending to help Slater and Madalyn, according to the prosecution.   

"He rescued Madalyn from the vehicle and noted that she had a small bump on her head and was crying, but she was alert and breathing,'' the brief said. "He reached out to assist the defendant, but the defendant stabbed him in the arm and grabbed Madalyn from him.''

The man's shoulder was dislocated by the force of the child being ripped away from him.

"While holding Madalyn by one arm, the defendant stabbed her and threw her further down into the ravine,'' court papers said.   

The wounded man returned to the roadside to call 911, which other motorists were already doing while observing the defendant grabbing rocks and piling them up where Madalyn had been thrown, the brief said.  

Sheriff's deputies reached the location a short time later and spotted Slater still in the ravine. He attempted to run away from them but was quickly apprehended. They asked where he had put the baby, and Slater was evasive, saying only that he "messed up" and wanted "the death penalty," according to the brief.  

Deputies and California Highway Patrol officers soon discovered the rock pile, noticing hair sticking out from underneath a rock. They removed the pile and found Madalyn dead. An autopsy later determined she had died from "multiple stab wounds" to the upper body, according to prosecutors.

The baby's mother ultimately recovered from her injuries, as did the man who tried to save the tot.  

Court papers allege Slater has been a serial domestic abuser, victimizing three women prior to the 2020 attack. He was convicted in 1995 of forcible sexual penetration and served two years in state prison. Under the terms of his parole, he was required to register as a sex offender.