Mechanism of alkyl benzene reaction with KMnO4/KOH to form carboxylic acids

[![alkylbenzene](https://i.stack.imgur.com/qCDiZ.png)](https://i.stack.imgur.com/qCDiZ.png)


I came across this reaction regarding formation of carboxylic acid by treating alkylbenzenes with KMnO4/KOH.
I know that alpha-(C-H) bond in this compound is easily broken down into radicals. Then it reacts to form


[![1st step](https://i.stack.imgur.com/KCDbJ.png)](https://i.stack.imgur.com/KCDbJ.png)


After this step mysteriously manganese reactions to form phenylmethanoic acid and all remaining alkyl carbon are oxidized to CO2
I want your help to understand the mechanism of this reaction and how manganese reacts further down the reaction.


