[need advice] Was it posible to issue an arrest warrant without any notice

yesterday an arrest warrant was issued by cop to my mother. as my mother read the warrant she notice that there is no complainant in the warrant so she ask who is the complainant. but the police who bring the warrant just say "just come with me in the office so that you will know who is the complainant". After that she was detained with no further details about who is the complainant. the only thing she remember is that they call someone who and ask who is the complainant and then period. just today we ask to have copy of the warrant that dont have a complainants name, but police in the station said they could not give the warrant cause the police that issue the warrant was not in duty. its seem to me that there something unusual in case of my mother. please help i really need help.ASAP

question 1; Is it really posible to issue arrest warrant in a estafa without prior notice.
question 2: Is A due Process was been made in favor for my mother or they just skip on something and just to let my mother pay for bail.
question 3: if ever we will pay for bail what should be the process next.

a warrant of arrest will have people of the philippines as the complainant.

you will have to check the prosecutor's records what happened to the notice that was sent to your address. normally there was a refusal to receive.

after bail, her arraignment will be scheduled.