How can a king be arrested?

Just caught up the last 2 episodes of PV

Lot happened in these episodes and the story moved ahead in leaps. Be it Mrinal's betrayal towards prithvi and her own feelings for him and her determination for her revenge from Singhdant, or Prithvi's trust for Mrinal and the first failure he faced in this journey as a son, a king and a lover , or Sindhuraaj's plan to get the throne by killng his own father and getting Mrinal and Prithvi arrested for it.

But what I didn't understand was how can a king be arrested even if he is accused to have been involved in the murder of former king? Does that mean Prithvi's mother as the maharani has higher authority than Prithvi or is it somewhere close to democracy where people rule the kingdom.

As of now I feel Maharani will get both Mrinal and Prithvi arrested. That means she will believe that Prithvi is involved in the heinous crime of killing his own father. Is that plausible as we saw Maharani trusted Prithvi a lot.

It's like board of directors of Malwa turned against their CEO Prithvi ..😆

Looks like Maharani announced Prithvi's arrest.

She took the decision by getting carried away in emotions and finally when Sindhuraaj's wife told her the truth, she got Sindhuraaj arrested showing she doesn't differentiate between her son's.