An appeals court panel has reversed the murder conviction of a mother accused of driving her teenage son and his friends to a Southern California park where a 13-year-old rival gang member was stabbed to death.

The 2nd District Court of Appeal panel ruled 2-1 on Monday that jurors in the case of 33-year-old Eva Daley were given an "impermissibly ambiguous" jury instruction during the 2008 trial.

Associate Justice Laurie D. Zelon wrote that case records don't show the jury based its verdict on a legally valid theory, so the conviction should be reversed.

Daley had been convicted of second-degree murder for the 2007 death of Jose Cano.

Prosecutors argued that Daley wanted revenge because Cano allegedly stabbed her son six months earlier.