A neighbor drops a note and flowers in front of the victims' house on Monday in Camp Springs. (Yue Wu/The Washington Post)

In the last moments of 3-year-old Laila Miller’s life, the girl’s father fired a .38 Special revolver inches away from her head and slashed her neck with a knife before engaging in a gun battle with police, Prince George’s County authorities said Monday.

County officials released the details as an investigation continued into the toddler’s death and the police shooting of her father, Frederick R. Miller, 38. Two of Laila’s relatives also were shot by Miller and remained in critical condition, they said.

About 1 p.m. Saturday, Miller arrived at his daughter’s Fort Washington home, where he shot her grandfather and great-grandmother, police said. Video from a neighbor’s surveillance system shows Miller then carrying Laila from the house to his car before leading police on a six-minute pursuit, said the county police chief, Mark A. Magaw.

“Somewhere, in the middle of this chase, he makes a conscious decision to kill his daughter,” Magaw said.

The pursuit ended after a wheel fell off Miller’s car on Branch Avenue, police said, and a shootout with five county police officers and one Maryland state trooper began. Miller died in his car during the exchange of bullets, with Laila in the front passenger seat, authorities said.

Prince George’s County State’s Attorney Angela Alsobrooks, center, talks to the press about the shooting on Monday in Camp Springs. (Yue Wu/The Washington Post)

Officers involved in the shooting at first feared they may have harmed the girl, Magaw said.

“These officers were resolute in what they did because they felt they had to do it,” Magaw said. “But they were torn that possibly one of the rounds that were fired may have hit this child.”

Magaw said that the bullet fragments found by medical examiners do not match any ammunition used by law enforcement officers at the scene and that Laila was shot by a gun held three to six inches away from her. Police concluded her father was the killer. It was unclear whether he fired before or after the attack with the knife.

“There is no one else who could have shot this baby girl,” Magaw said. “It’s heart-wrenching.”

Court records and interviews with family members and law enforcement officials indicate Miller had been suffering from mental health issues and had been engaged in a stormy custody battle for most of Laila’s life with the girl’s mother, Charmain Randolph.

Miller’s friends and relatives doubt police accounts of the events, saying he was a loving father who doted on his daughter, calling her “Princess Laila.” But on the advice of attorneys, they declined to elaborate.

“I believe Frederick would never harm his daughter,” said family attorney Tori Bramble. “The court system interfered with his unfettered access to his daughter, but he would never do anything to hurt Laila.”

Bramble has contracted with an independent investigator to review the circumstances of the shooting and car chase. “We have qualms with the police’s version of events,” Bramble said. “There is a lot that needs to be sorted through.”

Miller’s relationship with Laila’s mother was fractured at best, Bramble said.

Randolph could not be reached for comment.

In a 2011 court filing, Miller, a former Marine, sought sole custody of his daughter, worried that she was spending too much time with her grandfather. He also indicated that because he was not employed at the time, he was able to be a full-time caregiver. Miller’s family says he worried that his daughter was neglected.

Conflict between Laila’s parents escalated in November, after Randolph applied for a temporary protective order against Miller, alleging he vandalized her family’s home and their cars, court records state.

Randolph alleged that she had surveillance video showing that Miller marked a car and a garage door with the words “Liar” and “Liars don’t live long.”

“This is an ongoing problem with Mr. Miller for almost 3 years now and I am afraid for me and my child’s safety,” Randolph said in her request for a protective order. “I don’t know what Mr. Miller will do next.”

Randolph also indicated that her grandfather also had a peace order in place against Miller.

Bramble said family and friends do not know why Miller went to the Fort Washington house on Saturday. There was no indication in the previous days that something was wrong, family members said.

But Miller did suffer mental problems after a 2010 car crash, according to court records. He also had post-traumatic stress disorder after an August 1998 incident in which he physically over-exerted himself while he had a heart condition, according to his mother, Ana Garcia. Miller was honorably discharged from the Marine Corps in October 1998 and was awarded disability, according to military records provided by the family.

Court records show that in June 2010, Miller was rear-ended while traveling on U.S. 50 in Bladensburg. In a lawsuit Miller filed seeking damages against the other driver, his attorney claimed the accident caused a “severe brain injury, which has caused him to become disabled.” The claim lists a series of ailments Miller experienced after the accident, including headaches, short-term memory loss, a speech impediment, impulsive disorder and depression. The claim also states Miller would get confused and agitated easily. The case was settled out of court, according to records.

Prince George’s police say they will continue to investigate the case and focus on raising awareness about domestic violence in the wake of Laila’s death.

On Monday, the Prince George’s County state’s attorney, Angela Alsobrooks, gathered faith leaders and elected officials to call on men in the county to seek help before resorting to family violence. They encouraged residents to use the county’s confidential call center — 211 — for help.

“This is not an issue the criminal justice system can resolve,” Alsobrooks said.

Twelve of the county’s 34 homicides this year are domestic-related, authorities said.

“This investigation is not over until we can figure out why this happened,” Magaw said. “If we can figure that out, hopefully we can try to prevent it in the future.

Jennifer Jenkins, Mary Pat Flaherty , Peter Hermann and Mike DeBonis contributed to this report.