Map with the Id and RecordType does not works

Question

The below query works fine where setCaseId='hds88899889':

SELECT Id, DeveloperName FROM RecordType WHERE SObjectType ='Case' AND Id = :setCaseId

When I used it below not sure always results into no values

Set<Id> setCaseRTId = new Set<Id>();
for(case c : newCases) {  
    setCaseRTId.add(c.recordTypeId); 
} 
Map<Id, RecordType> caseMap = new Map<Id, RecordType>([ SELECT Id, DeveloperName
                                    FROM RecordType WHERE SObjectType ='Case' AND Id = :setCaseRTId]);
System.debug('Map Values ? : '+caseMap);