The photo shows a white police officer smiling as he bends over beside a black man's dead body. Wearing latex gloves, he gives a thumbs-up with his right hand and holds the man's limp arm in the other.
The name of the officer from the North County Police Cooperative in Missouri has not been released.
The deceased man is 28-year-old Omar Rahman, who was found dead last August in a home in St Louis County.
The photo has prompted an internal investigation by police officials and a likely lawsuit from Rahman's mother, Kimberly Stanton. She found out about the picture after a reporter, who was tipped off about the photo shortly after Rahman's death, showed it to her.
Stanton said the officer in the photo, the person holding the camera and anyone else who may have been in that room should be held accountable for their actions.
"I want them punished for what they'd done," Stanton told the Washington Post. "Because my child, he couldn't do anything. He was helpless. He was gone."
Police Chief Timothy Swope told the Post that the officer was positioning Rahman's body "to do proper crime scene investigation" and to check for any signs of trauma.
"That's exactly what we were doing," Swope said. "There's no malice there."
He acknowledged that the officer "may have used very poor judgment" for making a thumbs- up, saying the officer "should be more thoughtful of how that represents".
"We don't condone that," Swope said.
He declined to comment about the internal investigation, saying he cannot discuss disciplinary matters.
Stanton's attorney, Antonio Romanucci, said he plans to file a lawsuit alleging negligent infliction of emotional distress within the next two weeks.
"Clearly, this is a blatant example of disregard for human life," Romanucci said.
"When you take a photograph like that, the expectation is it will be seen by other individuals. They knew this photograph could've been seen by his mother. The smile that is on that officer's face as he's handling this human body is disturbing. I'm disgusted by it."
Romanucci said he is seeking several records from police officials, including memory cards used with the camera and who has used it within the past two to four years. He said he does not think the photograph is an isolated incident and that similar photos could have been taken in the past.
He also said he believes the photograph was racially motivated.
Swope said that was not the case, adding that the police department reflects the demographics of the communities it patrols. About 60 per cent of the police force are African Americans, he said. So are nine of 12 supervisors, including the assistant police chief.
Swope added that the photograph is not representative of the North County Police Cooperative, which was created last year by consolidating resources and disbanding smaller, cash-strapped police departments, according to the St Louis Post-Dispatch. The police department patrols several high-crime areas in north-central St Louis County, Swope said.
The controversial photo was first published Thursday by KMOV-TV, a CBS-affiliate, in St Louis. The photo was leaked to reporter Lauren Trager weeks after Rahman's death on August. 8.
The station said the death has been ruled an accidental drug overdose. KMOV blurred Rahman's body, as well as the officer's face, because police officials have not determined any wrongdoing.
The story has since prompted a simmering legal dispute between the TV station and the police department.
A lawyer for the agency sent a letter to KMOV's news director last week, saying the photo is stolen property and urging the TV station to return it and any copies of it.
"If KMOV is unwilling to cooperate with the NCPC, it may have no choice but to pursue other enforcement remedies available to it," Lynette Petruska wrote.
Petruska didn't return a call and answer an email from the Post.
In response, KMOV's attorney wrote an email Wednesday to Petruska saying the letter is "disturbing on both the law and the facts" and a "violation of the prohibition on prior restraints emanating from the First Amendment".
The lawyer's name was redacted from a published PDF file of the email.
"I urge you do some further research before you continue threatening KMOV-TV," the attorney wrote.
Petruska wrote back Thursday, saying that "no effort has been made to involve the judiciary in the suppression of any KMOV news story or to even suppress any purported story".
She also said that the photograph is part of a criminal investigation and is, therefore, considered private under Missouri's open records law. She reiterated that the picture was stolen and said the police department has to investigate the theft.
The picture has prompted several questions on social media about the officer's actions.
"Can we as humans be that insensitive?" wrote one Facebook user.
Some drew comparisons to the controversial photos at the Abu Ghraib prison in Iraq. Some photos from the prison showed soldiers posing over a detainee's body, smiling with their thumbs up.