1. Since you have protest petition the court will hear you to decide whether to add them as co accused person or to direct the Police for further investigation or treat the complaint as private complaint case.

2. So after the hearing you will be informed about the final outcome of the case on this issue

3. if your protest petition is allowed then it is alright. Else file revision in the sessions court.

Just relax and court will surely take some Appropriate Action and issue summons to all the accused

Once you file protest petition magistrate can direct police to carry on further investigations 

2) you can check the roznama ie court records as to whether order fir further investigations has been made by magistrate and report if any of police on further investigations 

Dear sir,

Please send me the relevant documents. If not included then you may file application under section 319 as follows before the magistrate.

1. The court will pass an order on your protest petition after recording your evidence. That is how you will come to know.

2. If summons are issued to AI only then it means that other accused have not been summoned. It is not clear from your query as to whether the order to summon A1 only has been passed before or after your protest petition. 

Dear Client,

How and why court will summon them until protest will not decide. Argue on protest petition , if allowed than court will summon them, or dismissed than file revision.

1. As per the information mentioned in the present query, makes it clear that though names of person from A 2 to A5 are there in the report, but summons had been issued to only A1.
2. You have rightly objected to it by filing the present protest petition. Now, proceedings will get conducted with respect to your protection petition concerning the points for the adjudication which are not adjudicated till now.
3. Though it can be seen that not even summons were issued to them, still o would suggest you to won’t get ready some information or proofs to prove their guilt also, and don’t let them go.
4. The purpose of protest petition is same as to do something which investigation may not have done accurately.

If you have filed a petition seeking to implead the other accused then the court will hear the petition by summoning the accused and also will hear the public prosecutor on this.

You can engage an advocate from your side and get to know the details  through advocate