After two trials without result, police officer Joseph Weekley will not face another trial for fatally shooting Aiyana Stanley-Jones, a sleeping seven-year-old, during a 2010 raid filmed by a reality TV show

Authorities won’t pursue a third trial of a Detroit police officer who fatally shot a seven-year-old girl during a night-time raid that was filmed by a reality-TV show, a prosecutor said on Wednesday.

Aiyana Stanley-Jones’s mother has been notified that Wayne County prosecutor Kym Worthy will move on Friday to dismiss the only remaining charge against Joseph Weekley, a misdemeanor count of reckless use of a firearm.

The girl was shot in the head while she slept on a living room couch in May 2010. Police were accompanied by a camera crew from The First 48, which recorded it from the outside, not inside where Aiyana was killed. The shooting was not considered intentional.

Weekley’s first trial ended without a verdict in June 2013. His second ended in October with a hung jury. During it, the presiding judge dismissed a charge of involuntary manslaughter.

Worthy called it “unfortunate” that Judge Cynthia Gray Hathaway dismissed the felony manslaughter charge, leaving only the misdemeanor count. It carries a maximum punishment of two years in prison.

“Under the law, her decision cannot be appealed,” Worthy said in a statement.

Aiyana’s grandmother, Mertilla Jones, said in a statement on Wednesday that “it feels like the system” failed their family.

Jones called Gray Hathaway’s dismissal of the manslaughter charge “even more insidious, given the fact that a seven-year-old child was killed while she was sleeping”.

Weekley’s attorney, Steve Fishman, said the prosecutor’s decision was “courageous” and “a correct one”.

Weekley has said he feels “haunted” by the tragedy. He was a member of an elite police unit and was the first officer through the door of the home during a chaotic search for a murder suspect.

Weekley’s submachine gun fired seconds after a stun grenade was thrown through a window to confuse anyone inside. He didn’t testify but has insisted that he mistakenly pulled the trigger during a struggle with Jones. Jones denies the struggle took place.

Ron Scott, a spokesman for Aiyana’s family and a founder of the Detroit Coalition against Police Brutality, said they will push the federal government to seek civil rights charges in the case.

“This kind of blatant disregard and militarization that destroys human life, we have to stop it and send a message that it will not be tolerated, especially in the lives of young black people,” Scott said.