A jury was discharged Thursday after failing to reach a verdict on a second British police officer accused of assaulting former Premier League star Dalian Atkinson.

Mary Ellen Bettley-Smith was accused of hitting Atkinson with a baton after he had had been tasered to the ground by police constable Benjamin Monk.

The case against Bettley-Smith, 31, ended in a hung jury a day after Monk was convicted of Atkinson's manslaughter and told by the judge he will face an "inevitable" jail term.

A six-week trial in Birmingham was told Monk fired a Taser three times -- including a single 33-second discharge -- and left two bootlace prints on Atkinson's forehead during the assault on August 15, 2016.

Jurors took nearly 19 hours to reach a unanimous verdict on Monk, whom prosecutors said had exaggerated the threat posed by the former Aston Villa player and lied about the events to justify excessive and unlawful force.

But having deliberated for more than 21 hours on the case of Bettley-Smith, charged with using unlawful force, jurors told the trial judge at Birmingham Crown Court they would be unable to reach a verdict even if given additional time.

Bettley-Smith, a former girlfriend of Monk, told her trial she used necessary force to defend herself and others.

But prosecutors claimed she had exaggerated the threat posed by Atkinson to support Monk's attempt to justify excessive force.