Pallbearers carry the casket of 3-year-old Ji'Aire Lee on Friday at Resurrection Cemetery in Clinton, Md. (J. Lawler Duggan/For The Washington Post)

She wiped away tears Friday at the funeral for her 3-year-old son, who was found dead on a park swing in Southern Maryland after she’d been pushing him for hours, possibly overnight.

Ji’Aire Lee’s small body, dressed in white, was laid out in a white casket at First Baptist Church of Highland Park in Landover, surrounded by sprays of white roses.

His 24-year-old mother, Romechia Simms, who’d been hospitalized for four days after his death, was among those singing “This Little Light of Mine.” Sitting beside her: Ji’Aire’s father, James “Donnell” Lee, 29, who sought custody of the preschooler in March because he was concerned about Simms’s mental stability.

Later, as pallbearers carried the casket to the burial site at Resurrection Cemetery in Clinton, Md., the two grieving parents held hands.

In the funeral program, Simms included a letter she’d written to Ji’Aire: “Son, the joy you brought to my life is unexplainable. . . . I miss you so much Ji’Aire, way more than I could possibly express through words. I am slowly accepting your passing. I want you to know that I have always been extremely proud of you, and I love you until the end of time. Ji’Aire Donnell Lee you are amazing. Love always, Mommy.”

James "Donnell" Lee mourns his 3-year-old son, Ji'Aire Lee, at a funeral service on Friday in Landover, Md. (J. Lawler Duggan/For The Washington Post)

Charles County sheriff’s deputies found Ji’Aire and his mother May 22 in Wills Memorial Park in La Plata after a neighbor who’d seen them the night before called police. The cause of death has not been determined, but Ji’Aire’s body showed no signs of trauma, authorities said. Detectives are still investigating what happened, and no charges have been filed.

On Friday, as gospel music spilled from speakers, photos of Ji’Aire as a newborn in baby blue tucked in his mother’s arms at a hospital flashed on video screens. More photos followed of him as a sleeping newborn, a crawling baby, a toddler sucking his thumb, swinging on a playground and in a blue shirt raising four fingers and grinning.

Ji’Aire’s obituary described him as a cheerful boy who enjoyed going outside and watching his cousins play football: “He loved bossing his cousin Jhai around and taking over his PS4. He loved watching movies with his parents such as ‘Scooby Doo,’ ‘Austin Powers’ (his favorite lines to quote are ‘Yea Baby’ and ‘Ohh Behave’), ‘Power Rangers,’ ‘Biker Boyz’ and the list goes on and on. He loved singing and dancing like his mother and father. You could always catch him grooving to a song making up his own dance showing the world his style.”

After the service, Ji’Aire’s parents walked out of the church behind the casket. Simms, whose hair was piled in a high bun, wore a black dress, a white sweater and low-heeled black sandals. Lee wore a white tuxedo jacket over black pants. Outside, in the church’s vestibule, mourners hugged them. A white hearse led the procession along winding Prince George’s County roads to the cemetery in Clinton.

Diane Richardson, a spokeswoman for the Charles County Sheriff’s Office, said this week that investigators are still awaiting toxicology reports.

“We are focused on finding out what happened to the child,” Richardson said. “Our detectives are very compassionate yet very focused. We are working hard to get answers.”

Romechia Simms and her 3-year-old son Ji'Aire Lee after his first haircut in March at St. Charles Mall. His funeral is being held Friday after he was found dead on a park swing being pushed by his mom. (Courtesy of family)

Simms, who suffers from depression and bipolar disorder, had what her mother, Vontasha Simms, called “some kind of a psychotic episode” in the park. She was taken to a hospital by sheriff’s deputies for treatment and discharged four days later.

Romechia, who had suffered a mental breakdown in February, doesn’t remember what happened in the park that night, family members said.

Vontasha Simms, 47, said she believes Romechia would never have intentionally hurt her son. But he had a bad cough, and the temperature had fallen to about 51 degrees overnight, according to National Weather Service data.

Ji’Aire’s death had fueled tensions between the families of his mother and his father.

Lee, 29, who lives in Southwest Washington, had filed for full custody of his son in March, saying in a petition in D.C. Superior Court that he was concerned about Simms’s mental health. She had been behaving erratically, he told the court, including jumping from a moving taxi.

“I do not believe she can safely care for our son,” Lee wrote.

In her response, Simms told the court in April that she had recovered from her breakdown and was the better, more capable parent. “I have done everything in my power since moving from D.C. to ensure that my son has the best life that he can have,” she wrote.

At a hearing on May 11 — just 11 days before Ji’Aire’s death — the parents agreed to share custody, with Lee taking him on the weekends and Simms keeping him during the week.

Lee didn’t bring up Simms’s mental state or reiterate his fears about his son’s safety, a transcript of the hearing shows. And D.C. Superior Court Judge Peter A. Krauthamer did not press either parent on Simms’s mental state, though he did ask, “Is someone unfit here?”

“There’s no one unfit,” Lee responded.

At the boy’s funeral Friday, Ji’Aire’s father expressed his sorrow with a poem included in the funeral program: “Precious God, I know you gave your precious Son/ To give us life with You./ But I didn’t want our son to leave,/ Cause he was precious too./. . . Our precious son is with you,/ And there will be a day/ That we too will leave this earth/ And you will light our way. His arms will be wide open/ And the wait will be worthwhile/ When we see again our precious son/ And the splendor of his smile. Love you forever — Dad.”

Under a green tent at the burial site, Lee and Simms sat next to each other on folding chairs as mourners sang, “Come by here, my Lord.” After prayers, the Rev. Henry P. Davis III asked everyone to give the mother and father one last moment alone with their son.

Simms and Lee laid bunches of long-stemmed white roses on the casket. Then they clasped hands and walked back to the waiting hearse. Romechia Simms was clutching a tiny brown teddy bear.