How about these?

[Rasa]

These sentences are straight forward in the way English people use or not?

1. Investigation on being the sole person exercising parental power over the child.
2. Investigation into the provision on maintenance.

In another quote someone said "investigation into" is correct, so how about the above sentences, please? [quote][/quote]

[Parasha]

Neither of them sound entirely right to me.

It would help if you could post complete sentences, or tell us what the story is behind them. I do not understand what you are trying to say, from what you have given.

[Naomi]

sounds like a custody and financial support problem.

post background - AND, very important, which country this is for - and I'll take another look. I can help with US and British legal English, but not with Australian etc.

[Guest]

These sentences are straight forward in the way English people use or not?

1. Investigation on being the sole person exercising parental power over the child.
2. Investigation into the provision on maintenance.

In another quote someone said "investigation into" is correct, so how about the above sentences, please?

Thank you for your interest in this topic:- I actually try to say a statement on an official document, something like a Memorandum which a mother tries to confirm herself as a single person who provide custody to he child without the help of her husband who has deserted her without coming back to her any loger, and she then requests the District Officer to issue a letter certifying that she is the only one person who has taken care and provided custody or upbringing to the child, so that when her child requires to apply for passport, it will not require the father of the child to give a consent. That means that she has to ask the officer to make an inquiry into the child custody (or the child's upbringing). Thank you again.([quote)