Apply for and obtain Anticipatory  bail from sessions court 

2) burden of proof is upon prosecution to prove allegations beyond reasonable doubt 

3) you ha e to in your statement take the plea that work was done under your supervision 

4) rely upon site reports which bear your signature that you were visiting site regularly and submitting reports to your superiors 

See at this stage anticipatory bail can be taken and a quashing petition can be filed before the high court that the work was supervised and later it was damaged and the engineer was not responsible for the damage. 

Engage a senior criminal lawyer to defend you.

the offence is 304 A , regular bail is possible , some documents are required for better understanding of the case.

In this case it is clear fault of Junior and assistant engineer until school can prove that the pillars was demolished by some unknown person.

Here school is also at fault because they have not informed any senior official or police complaint regarding demolision of pillars and continue taking the classes in same premises in this case officers of school me also be charged by same offence.

It was visible that pillar support is damaged by unknown person due to which it collapsed, so culpability of school administration is more. 

Mere improper supervision that also after 10 years cannot impute on engineer as construction is subject to wear and tear and needs maintenance.

Actual reason of collapse is pillar damage and not poor quality of material.

And possibility cannot be denied, that report is managed by school administration to avoid its responsibility.

More truly, school administration responsible, maximum engineer can be involved as co accused but not actual accused.

FIR will be lodged against the concerned offenders by the state in this case as people have died

1. If the FIR has been obtained then apply for and obtain anticipatory bail so that you do not suffer arrest and detention.

2. Once you secure bail you will have to face the case on merits and prove your innocence at trial unless there is scope in the FIR to seek quashing of it.

1. As per the information mentioned in the present query, makes it clear that there are serious allegations against the accused.
2. Firstly, they would have to apply for Anticipatory Bail as otherwise they might get arrested also.
3. And try to show in the Bail application that you have gone through with each and everything, and used the good quality material.
4. Rest, would have to go in accordance of the prosecution evidences and then would have to prove that wrong by contradicting the same evidences.

You better collect the evidences of somebody damaging the pillar twice as you said and secure the evidence to utilise them during trial proceedings.

First you obtain AB and then wait for the charge sheet to be filed.

After that on the basis of the evidences in your possession you may even file a petition to quash the charge sheet before high court under section 482 cr.p.c. 

Collecting the evidence in yor favor is very vital, do it somehow.