A 7-week-old girl who died on Christmas Day in Southwest Washington was malnourished and suffered broken ribs, according to D.C. police, who on Friday arrested the parents and charged them each with first-degree murder.

An arrest affidavit describes the infant, Trinity Jabore, as living in an apartment with three other children — ages 15 months, 5 and 8 — littered with dirty dishes, trash and cigarette butts, as well as evidence of drug use.

Police said the parents fed Trinity formula given to them by the hospital, but later began using water mixed with condensed milk. The medical examiner said Trinity died of starvation, trauma and hyponatremia, or forced water intoxication. The death was ruled a homicide on Wednesday.

On Friday, police said that they arrested Trishelle Jabore, 26, and Jay Crowder, 33, identified as the infant’s parents. Each was charged with first-degree murder .

The affidavit says that Trinity was born Nov. 6 and was discharged two days later weighing 4 pounds, 11 ounces. The infant tested positive for marijuana, the affidavit says. The mother, unable to breast feed, was sent home with two boxes of pre-mixed formula, each containing eight five-ounce bottles.

Police said that when the formula ran out, the parents purchased one other container of formula. Police said that the refrigerator in their apartment in the first block of Galveston Place SW was stocked with food, but none that the baby could eat.

Police said that the couple went grocery shopping at two stores on Dec. 2 and spent $450.90, but only $12.99 on one 23-ounce box of baby formula.