Last Sunday, Ismael Lopez, 41, an auto mechanic originally from Veracruz, Mexico, was shot and killed by police officers in Southaven, Mississippi, a suburb of Memphis, Tennessee in what officials have described as an apparent address mix-up. The attorney for Lopez’s family claims that he was shot in the back of the head execution style through the front door of their home.

A statement released by Lopez’s family last week said he was a loving husband and father, a hard worker, and a mentor in the community. “There is no reasonable explanation about why or how this happened to our Ismael, but we believe his memory demands answers, accountability and justice.”

Lopez had been a resident of the neighborhood for 13 years, and the only time the police had ever been to his home was when the family had been robbed. The officer who killed Lopez, unidentified as of this writing, has been placed on administrative leave.

On Friday, attorney Murray Wells, who is representing the wife and son of Lopez, contacted the Justice Department to demand a federal investigation of the incident, saying that they believe the man’s death was an execution and that the officers involved should face criminal charges.

According to District Attorney John Champion of northern Mississippi’s DeSoto County, two officers were present Sunday evening when Lopez was killed in his home. Champion stated last week that those officers fired their weapons after a dog “burst” out of the house as they searched for a suspect and claimed that Lopez had pointed a gun at them through an open door. Champion stated that the officers began shouting “put the gun down, put the gun down,” after which they fired multiple shots toward the door.

Wells, however, gives a different account. After hiring investigators and interviewing Lopez’s neighbors, he discovered that police did not have a warrant for Lopez and were at the wrong address. He also reports that Lopez was shot through a closed front door and that he did not have a gun in his hand when he was killed. Wells stated earlier last week that “this is incredibly tragic and embarrassing to this police department that they can’t read house numbers.”

An official autopsy report by the county coroner or a doctor has not been released and could take up to eight weeks to complete.

According to local media reports a sheriff from a neighboring county had requested that Southaven police look for a domestic violence suspect who was not Lopez. The Southaven Police Department claims that the officers were supposed to serve a warrant to Samuel Pearman, who lives across the street from Lopez.

Wells also disputed this claim, pointing out that Pearman had been identified and questioned by police as a possible witness to the shooting and was not detained as would be expected for someone with a warrant out for their arrest. “There was not an active warrant in effect on July 23. They were not, in fact, executing a warrant,” Wells noted. A warrant was not put out on Pearman until July 24, the day after Lopez was murdered by the police.

“I wound up talking to the police that night too. They wanted to know what I heard. They said they were responding to a shots fired call,” Pearman stated in a Facebook Live video recorded just before he was arrested earlier this week on domestic abuse charges.

“We haven’t talked to Mr. Pearman. We have been fortunate enough to let the press do some of that for us. So, we’ve been able to see his position. From what we understand, he’s terrified himself. He believes that he was the target of a coordinated effort to execute him,” Wells said at a public news conference in Memphis on Friday. “I don’t know the truth of that statement, but they sure came in guns a-blazing, I guess believing that Mr. Pearman was in there without an active warrant.”

Lopez’s wife, Claudia Linares, claims that Lopez never had a gun in his hands and that police started shooting despite the family’s door being closed. A family friend relayed, “She said when he got up, she heard footsteps all the way up to the door, she heard the doorknob turn, and then after the doorknob turned it was just gunshots from there.”

“We think it was an execution,” Wells explained. “Now, when you’re firing through a door, we think it complicates things. Physical evidence says their story isn’t true.”

Wells suggested that “[t]his man died while running away from people who were trespassing on his premises.”

The attorney also made a case that police and city officials are covering up facts about the shooting.

At this point in time, the Mississippi Bureau of Investigation is still performing their investigation and will turn their findings over to Champion, who will decide whether to pursue charges. Southaven police have referred questions to the bureau, which did not immediately return a call from the media seeking comment. The DeSoto County coroner had also failed to return similar calls.

In addition to criminal charges being brought against the officers involved, Wells also called for their resignation as well as that of the Southaven police chief. He told reporters that he was contacting the Justice Department asking them to bring in federal investigators.

Federal investigations into police killings are incredibly rare and regularly concluded without charges being brought or prosecutions. Attorney General Jeff Sessions has promised to pull back even the pretense of federal oversight put in place by the Justice Department during the Obama administration.