Boy, 4, was beaten to death for spilling his cereal, police say. Now, his mother and her boyfriend are on trial for murder.

When 4-year-old Tahjir Smith spilled his cereal on a January morning last year, prosecutors say, his mother and her boyfriend beat him to death.

On Tuesday, in a Norristown courtroom, the lawyers described for a jury the last terrifying moments of the boy’s life. They said the couple beat him about the head and body with their hands and a sandal until he fell unconscious in their Abington home, and then put him in a shower and ran scalding water over his body.

The narrative of events on Jan. 22, 2018, marked the start of the murder trial for Tahjir’s mother, Lisa Smith, and her boyfriend, Keiff King.

Hours after the beating, at 6:09 p.m., when the child was likely beyond resuscitation, prosecutors said, Smith called 911 to report that he was suffering from an asthma attack. When paramedics arrived, they found the boy’s body riddled with fresh bruises.

Smith, 20, and King, 27, face charges of first-degree murder, conspiracy to commit aggravated assault, and related crimes.

Lawyers for Smith and King said the couple was under stress at the time and did not intend to kill Tahjir.

“An outcome does not equal intent,” said Smith’s public defender, Carrie Allman. “Ms. Smith did not intend to kill her child.”

Prosecutors countered that Tahjir, a 3-foot, 6-inch, 42-pound boy, had suffered months of escalating physical abuse at the hands of Smith and King. They said he had scars on his back, likely from being beaten with a belt, along with numerous fractured ribs and bruises on his face. In the past, they said, he had suffered the occasional black eye.

On the day he died, prosecutors said, Tahjir — just a month from his fifth birthday — had gone into shock from the beating. Forensic pathologist Ian Hood testified Tuesday that the boy’s brain was swollen and his ears were bruised, and he had second-degree burns on a shoulder from being scalded in the shower after the beating.

In court, Smith and King, who met three years ago in Southwest Philadelphia, sat quietly at the defense table. At times, Smith, in a modest orange dress and tan cardigan, wrote on a legal pad. King, in a gray sports coat, kept his hands together, head bowed.

Smith’s lawyer said her client, then 19, was six months pregnant with a second child and taking care of King’s 4-year-old daughter and 3-year-old son, along with Tahjir, on this day of his death. Smith fed the three children breakfast around 9:30 a.m., the lawyer said, then cleaned the house in preparation for home-health aides who were coming to help care for King’s grandmother, who was suffering from dementia. King slept in until 11 a.m., she said.

Of the fatal beating, Allman said, “This is criminal conduct without question, but it’s not murder.”

King’s lawyer, Francis Genovese, also tried to persuade the jury that the couple’s actions did not rise to the level of first-degree murder.

Prosecutors said Tahjir’s death was the culmination of a long pattern of abuse. In fact, they said, on the night of the child’s death, under questioning by Abington police, his mother confessed.