What is 'ta'zir' under which Saudi Arabia executed a Bangladeshi 'couple'?

Saudi Arabia executed a Bangladeshi man and woman in Mecca after sentencing them to death under ta’zir for an indecent act inside a mosque. Under Islamic law, ta'zir is a discretionary offence that doesn't have a fixed and mandatory punishment, DNA reported. The judge or state authority determines the punishment based on the offence, the offender’s character and public interest.