A father was shot and killed by police in a case of mistaken identity, his family’s lawyer has claimed.

The attorney is pressing for officers to face criminal charges, calling the victim’s death an execution.

Car mechanic Ismael Lopez, 41, was shot dead at his Mississippi home on Sunday.

Officers were hunting a man suspected of assault, according to an incident report. But they arrived at the wrong address in Southaven, stopping at a house number across the road from the location shown on their warrant.

At this point, accounts of the incident diverge.

According to the state’s DeSoto County District Attorney John Champion, two officers knocked on the door. The Lopez family did not hear the knock, but their pitbull did and started barking. Mr Lopez then opened the door to investigate, and his dog charged out at officers.

Mr Lopez held a gun at the officers and did not lower it when asked, so officers shot him.

However the family’s lawyer, Murray Wells, says an independent investigation into the death revealed a different version of events.

Mr Lopez died from a single bullet to the back of the head, he said. There are bullet holes in the door of the home, which Mr Lopez never opened, suggesting police shot the victim through a closed door.

Mr Lopez was unarmed when he died, he said.

“This man died running away from people who were trespassing on his premises after he was in bed lawfully", he told reporters at a news conference on Friday.

"We think it was an execution."

"When you're firing through a door, we think it complicates things. Physical evidence says their story isn't true."

The coroner’s report has not been released yet. Southaven police have also not released their police incident report.

The Mississippi Bureau of Investigation is examining the case. It will inform the District Attorney on whether to pursue charging the police officers.

The family’s lawyer said he will request a federal investigation from the Department of Justice.

"There is no reasonable explanation about why or how this happened to our Ismael, but we believe his memory demands answers, accountability and justice," Mr Lopez’s family said in a statement.

Mr Lopez was "a loving husband, guiding father, mentor to the youth in this community and a hard worker".