A white Texas police officer who entered an apartment mistaking it for her own and shot dead the black man who lived there was arrested on manslaughter charges.

Officer Amber Guyger with the Dallas Police Department was arrested Sunday and booked into the county jail, the Texas Department of Public Safety said.

At the end of her shift and still in uniform, Guyger entered the apartment in a complex near downtown Dallas late Thursday and shot a man who she thought was an intruder, police said.

Minutes after shooting she called emergency services and told responding officers that she thought she had entered her own apartment.

The victim, an African-American, was identified as Botham Shem Jean, 26, an immigrant from the Caribbean island nation of Saint Lucia.

Jean had graduated from a private Christian college in the state of Arkansas in 2016 and had since been working at the accounting firm PricewaterhouseCoopers in Dallas.

Wrong floor, open door

According to the Dallas Morning News, Guyger got off on the wrong floor of the building complex and approached an apartment exactly one floor above her own.

The door was unlocked and the lights were off and when Guyger saw a figure moving in the dark she pulled out her pistol and opened fire thinking it was an intruder, the newspaper reported.

Dallas police said that Guyger, 30, has been with the department for four years. Local reports said she was involved in an earlier shooting in May 2017.

The Dallas-Fort Worth NBC affiliate reported that Guyger was released late Sunday on a $300,000 bail.

Dallas Police Chief U. Renee Hall took the unusual step of handing the case over to the Texas Rangers -- a division of the Department of Public Safety -- to “eliminate the appearance of any potential bias”, police said in a statement.

“On behalf of the Dallas Police Department, we are continuing to pray for Mr. Jean's family, and ask that the community remain patient as this investigation is conducted,” Hall said.

Hall, who is African-American, became the city's first female police chief in September 2017. Jean's mother Allison Jean, earlier told NBC News that the incident “feels like a nightmare”.

Her son “was in no wrong place at any wrong time. He was in his sanctuary, in the place where he called home. He didn't deserve this,” she told NBC.