A Seattle police watchdog agency has launched an investigation after bodycam footage emerged of a police officer joking about the death of a 23-year-old Indian student after she was struck by a speeding police patrol car earlier this year, media reports said.

Jaahnavi Kandula was killed in January after she was struck by a police vehicle driven by Officer Kevin Dave. He was driving 74 mph (more than 119 kmph) on the way to a report of an overdose, The Seattle Times newspaper reported on Monday.

In bodycam footage released on Monday by the Seattle Police Department, Officer Daniel Auderer laughed about the deadly crash and dismissed any implication Dave might be at fault or that a criminal investigation was necessary.

In the clip, Auderer, the vice president of the Seattle Police Officers Guild, was on a call with the guild's president, Mike Solan. He laughed several times, saying at one point, "Yeah, just write a cheque."

"Eleven thousand dollars. She was 26 anyway," Auderer said in the video, misstating Kandula's age.

"She had limited value," he was quoted as saying.

Auderer said that Dave's vehicle had been "going 50" and that "that's not out of control," NBC News reported.

A police investigation report referred to prosecutors for review last month said that Dave had been driving at 74 mph, and Kandula was thrown more than 100 feet after the impact.

"That's not reckless for a trained driver," Auderer said in the video, adding that he doesn't believe "she was thrown 40 feet either," the report said.

"But she is dead," he said, laughing and adding, "No, it's a regular person."

Only Auderer's side of the conversation was audible in the bodycam footage.

Meanwhile, Auderer said that he made the comment as a mockery of lawyers, according to KTTH radio station in Seattle.

He noted that Solan "lamented" the young woman's death during the two officers' initial conversation, adding that it was unfortunate that her death would "turn into lawyers arguing 'the value of human life.'"

"I responded with something like: 'She's 26 years old. What value is there? Who cares?' I intended the comment as a mockery of lawyers," Auderer was quoted as saying. "I was imitating what a lawyer tasked with negotiating the case would be saying and being sarcastic to express that they shouldn't be coming up with crazy arguments to minimise the payment," he added.

"I laughed at the ridiculousness of how these incidents are litigated and the ridiculousness of how I watched these incidents play out as two parties bargain over a tragedy," the officer said.

According to the report, Auderer acknowledged that anyone listening to the body-camera recording "would rightfully believe I was being insensitive to the loss of human life" and said the comment "was not made with malice or a hard heart."

The Office of Police Accountability confirmed that an investigation had been initiated after the agency received a complaint on August 2 from an employee with the Seattle Police Department.

The oversight agency, which investigates police misconduct and recommends discipline to the police chief, is investigating "the context in which" the statements were made and whether any policies had been violated, the police department said.

Kandula, who hailed from Andhra Pradesh, had been pursuing her master's degree at Northeastern University in Seattle, according to a GoFundMe fundraiser launched to support her family.

"The family has nothing to say," her uncle, Ashok Mandula, was quoted as saying in the report.

"Except I wonder if these men's daughters or granddaughters have value. A life is a life," he said.?

Meanwhile, another Seattle police oversight organisation, the Community Police Commission, described the audio as “heartbreaking and shockingly insensitive.”

"The people of Seattle deserve better from a police department that is charged with fostering trust with the community and ensuring public safety," it said in a press release.

“Especially in light of this video, the hard work toward ensuring that the Seattle Police Department reflects the values of the community it polices, and embraces transparent accountability, will remain a top priority for the Seattle Community Police Commission," it added.