A new report says the 600 shots police fired at the chaotic end to a California bank robbery that left a hostage dead were excessive and unnecessary, with some officers only firing their weapons because other officers were shooting.

The report released Monday by the nonprofit Police Foundation also found some Stockton police officers opened fire with their colleagues standing right in front of them. The report said a lack of planning was partly to blame for the unnecessary shooting.

"In reviewing dispatch tapes and in response to interviews, the review team determined there was no planned response for when the suspect vehicle stopped," the report concluded. "This lack of planning, along with the number of officers involved, created a level of chaos that was difficult to manage and overcome."

The July 2014 shootout left two of the suspects and a hostage, Misty Holt-Singh, dead. Police have said Holt-Singh, 41, was struck by 10 of the bullets officers fired as she was used as a human shield by the sole surviving suspect, Jaime Ramos. Ramos has been charged with three counts of murder in addition to robbery, kidnapping, carjacking and gang counts. He has pleaded not guilty.

Stockton police had requested the review by the Police Foundation. Police Chief Eric Jones said in a statement the department intends to learn everything it can from the report and use it to improve.

"There are elements of this report that are tough for us to read," he said. "But it's important that we be as brave in reviewing this incident as our officers were in responding to it."

Joe Marchelewski, a spokesman for the law firm representing Holt-Singh's family, said the firm had no immediate comment on the report. It has scheduled a news conference with Holt-Singh's husband, Paul, on Tuesday for a discussion of the Police Foundation report and the Singh family filing a lawsuit. The family's attorney, Gregory Bentley, has said police should not have fired on the robbers as long as Holt-Singh was exposed to danger.

Police Foundation President Jim Bueermann praised Stockton police as heroes in a foreword to Monday's report, saying no police agency in the country had ever dealt with a similar situation.

The three suspects, armed with handguns and an AK-47, robbed a Bank of the West branch on July 16 and took three women hostage before fleeing in a bank employee's SUV.

Holt-Singh, one of those hostages, had gone to the bank with her 12-year-old daughter, who sent a text message to her father, according to the report. "Leave work. Bank got robbed. They took mom," the message read.

The suspects then led police on an hour-long pursuit and gun battle during which they fired about 100 shots from the AK-47 and shot up more than a dozen police vehicles.

Officers texted loved ones during the pursuit, some fearing they might not survive, according to the report.

One of the hostages, bank manager Kelly Huber, was shot by one of the suspects and either jumped or was pushed out of the vehicle. The other hostage, Stephanie Koussaya, a bank teller, said she couldn't believe the suspect in the back was shooting at police, according to an interview included in the Police Foundation report. She realized police were firing back and tried to duck behind the driver, but one of the suspects pushed her up.

She said she eventually jumped from the SUV.

"When I saw the SWAT team and its vehicle, I knew it was going to go badly. I knew I had to get out," she said, according to the Police Foundation report. "My whole thing was, 'I wasn't going to die that day.' "