Many nights Delberta Manuel Almaraz can be found sitting alone in her daughter's bedroom, where she cries as she stares at dozens of beaming photographs of her little girl framed and taped to poster boards and the sympathy cards lying on a table.

More than 14 months have passed since a Mesa police officer's stray bullet took the life of 15-year-old Celestina Manuel, and still her mother and family struggle to adjust to life without the girl who had a love for animals, singing and cooking breakfast for her parents.

"She was the only one in my family that was really affectionate," Almaraz said, crying as she remembered Celestina, the second-youngest of 10 kids. "She always told us she loved us. We miss her a lot."

Celestina's family has learned little since the shooting May 28, 2009. They hope a lawsuit filed June 28 in U.S. District Court against Mesa, Detectives Nathan Schlitz, his partner Nicholas Lien and Officer Alicia Reagan, will provide crucial answers.

"They want to know the truth," said Almaraz's attorney Barry Shalen, who has accused the officers of acting negligently and using excessive force against Celestina.

The officers were cleared of wrongdoing by the department, but Almaraz seeks damages in court.

City Attorney Debbie Spinner was in trial Thursday afternoon and not immediately available for comment. The city, however, typically does not comment on pending legal matters.

The incident centers on Celestina's cousin, Gumercindo Balderas, and a fistfight that broke out in the parking lot at an apartment complex at 1415 N. Country Club Drive. As police responded, Balderas jumped into his Ford Mustang and nearly ran down an officer.

What ensued was a 4-mile, 100-mph chase through city streets and onto the Salt River Reservation. Balderas slowed to 20 mph as he turned north onto Mesa Drive, a police car clipped the Mustang from behind sending it spinning to a stop, police reports state.

Balderas "was attempting to again run over" Lien, and Schlitz "fired shots into the car," Assistant City Attorney James Fritz states in court documents.

In all, five shots were fired into the car, which had dark tinted windows, according to a police report. Balderas was struck and then hit with a Taser before being pulled from the car.

The officers then found Celestina slumped over in the back seat, with a bullet wound to the head.

Celestina "knowingly assumed the risk of physical injury when she chose to ride in (Gumercindo Balderas') vehicle and sit in the back seat," Fritz states. Balderas' actions "rose to the level where defendant officers Schlitz, Lien and Reagan feared the threat of serious physical injury or death."

Because of that, Fritz states, neither the city nor its officers are liable for Celestina's death.

The Police Department's use-of-force policy allows an officer to use deadly force "in defense of life or to stop a fleeing felon," but states an officer must first warn the person. An officer is prohibited firing to disable a moving vehicle, but can use deadly force against an occupant, the policy states.

A Mesa police spokesman did not know if any changes were made to the department's use-of-force policy and didn't return messages for comment. However, Officer Nate Gafvert, a representative of the Mesa Police Association union, said he couldn't recall that any changes to the policy or training were made.

"Our training is designed to stop the situation as quickly as we can," Gafvert said. "In this situation, the suspect attempted to kill police officers, not once, but twice. They had to react to prevent the situation from getting worse."

While "unfortunate" that Celestina was struck by Schlitz's gunfire, the officers reacted based on the information they had, he said.

"In this case, (Celestina) was hiding in the back seat," Gafvert said. "Unless you're Superman . . . you cannot see what's going on in there. These officers acted on what they knew at that moment."

Balderas recently began serving a seven-year prison term on felony charges of aggravated assault and unlawful flight stemming from the chase. He will be placed on probation for two years after being released from prison.

Because the shooting occurred on an Indian reservation, the FBI investigated that part of the incident. Special Agent Manuel Johnson said the FBI has completed its investigation, which was forwarded to the U.S. Attorney's Office for possible prosecution.

U.S. Attorney's Office spokesman Wyn Hornbuckle said the case was reviewed and prosecution was deferred to Maricopa County Superior Court. No new criminal charges have been filed against Balderas in county court.