Police are investigating the murder of a mother and her 2-year-old daughter after they were fatally shot in a parking lot around about 7 a.m. Tuesday in Prince George's County. (WUSA9)

His 2-year-old daughter was sitting in her car seat when he turned the gun on her and opened fire, police said. He had gone to the girl’s Fort Washington home early Tuesday morning and waited for her mother to leave the house to confront her about the $600 in monthly child support he recently had been ordered to pay, according to police and court documents.

The disagreement over those payments turned violent, police said, leaving NeShante Alesha Davis, 26, and her daughter, Chloe Nichole Davis-Green, dead.

Daron Maurice Boswell-Johnson, 25, was charged with two counts of first- and second-degree murder in relation to each death after he admitted to killing his daughter and Davis, Prince George’s County law enforcement officials announced Wednesday.

Boswell-Johnson was arrested in Montgomery County on Tuesday shortly after police began investigating the double slaying at the Pinewood Hill Condominium on Palmer Road, said Hank Stawinski, the county’s interim police chief.

“While this resolves [the case], this is not a happy circumstance,” Stawinski said at a news conference Wednesday evening. “This is a callous and cold-hearted crime.”

Daron Maurice Boswell-Johnson, 25, is escorted by detectives after his arrest. (Prince George's County Police Department)

Davis was on her way to her job as a teacher and was taking her daughter to day care just before 7 a.m. Tuesday when Boswell-Johnson confronted her in the parking lot of the townhouse community, police said. Shots were fired, leaving Davis dead outside her home and her wounded daughter nearby in a dark-blue sedan. The girl was taken to a hospital, where she died.

Boswell-Johnson and Davis had had an ongoing disagreement over child support payments, police said. Court records indicate that Boswell-Johnson was ordered in November to pay $600 in monthly child support for Chloe after a DNA test indicated that he was her father.

Boswell-Johnson told detectives that he drove to Davis’s home, “parked down the street and waited nearby for her to exit her residence,” charging documents state. He then “approached her at gunpoint and demanded that she drop her ongoing child support petition.”

“The windows [of the car] were not broken in,” Prince George’s County State’s Attorney Angela D. Alsobrooks said at the news conference with Stawinski. “The door had to be opened in order for the baby to be shot.”

Immediate family members of Boswell-Johnson’s could not be reached or did not return calls seeking comment Wednesday, and it is unclear whether he has an attorney.

Boswell-Johnson’s cousin Raynardo Boswell said he was shocked to learn about the arrest. Boswell said that he did not know of any problems his cousin might have had and that the family has been “crying and crying” over the news of the charges against him.

“This doesn’t sound like him,” Boswell said. “He’s a good boy. He’s a good man. He takes care of his kids.”

Mapping homicides in the District and the surrounding suburbs since 2000.

Boswell-Johnson has two children from another relationship, and he requested sole custody of them in 2014, according to court records filed in Prince George’s County. That case was dismissed after neither party appeared for a conference, court records indicate.

The death of Davis and her daughter mark the third and fourth domestic-related homicides among the 10 killings the county has recorded this year, police said.

Alsobrooks said her office would aggressively investigate and prosecute the case to “bring Mr. Johnson to justice and bring peace to this family.”

But Alsobrooks also urged the community to work on how it can address family violence before more such killings occur.

“We are tired of talking about babies dying in our community,” Alsobrooks said. “These cases can’t be resolved here at the police station. They can’t be resolved at the courthouse.”

Davis graduated from Bowie State University last year and was a second-grade teacher at Bradbury Heights Elementary School in Capitol Heights.

The killing of Davis and her daughter stunned friends, family members, neighbors and students at Bradbury Heights. Many had wondered Tuesday who could have committed such a crime. The apparent resolution of the case Wednesday was bittersweet.

“These circumstances do not lead us to celebrate,” Stawinski said. “Coming and talking about the death of another child, it’s unacceptable.”

Matt Zapotosky and Jennifer Jenkins contributed to this report.