Variable does not exist - Batch Apex Query

Question

I have a Batch Apex which is invoked from process builder. I can see Ids are coming into the variable (please see debug log) but same variable inside the query gives "Variable does not exist" error. I am not sure what am i doing wrong here??

public class CaseSetOwnerBatch implements Database.Batchable<sObject> {    
List<String> csIds;

    public CaseSetOwnerBatch(List<String> csIds) {
        this.csIds = csIds;
    }

    @InvocableMethod(label='Set Owner to Parent Case Owner' description='This method will be execute CaseSetOwnerBatch')
    public static void executeBatchMethod(List<Id> caseIds) {
        System.debug('Case Ids: -- -- '+caseIds);
        CaseSetOwnerBatch setOwner = new CaseSetOwnerBatch(caseIds);
        Database.executeBatch(setOwner,1);
    }


    public static Database.QueryLocator start(Database.BatchableContext BC) {
        String query = 'SELECT Id, OwnerId, LastModifiedById FROM Case WHERE Id IN :csIds';
        return Database.getQueryLocator(query);
    }
public void execute(Database.BatchableContext BC, List<Case> csList) {  
        for (Case c : csList) {
            c.OwnerId = c.LastModifiedById;
        }
        TriggerHandler.bypass('CaseTriggerHandler');
        Database.update(csList, false);
    }   
    public void finish(Database.BatchableContext BC) {
    }
}

Answer 1

Remove static from the method signature. It will work as expected.

Go through batch apex document: https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_batch_interface.htm