SQL & PL/SQL

I have below query where i am trying to use case when condition in where clause but its throwing an error from the first case when condition as 'ORA - 00905 missing keyword'.

create or replace procedure chk_kpi_reactivate_downtime as 
begin
  Select DISTINCT(KD.KPI_NAME),DS.TEMPLATE_NAME 
  from RATOR_MONITORING_CONFIGURATION.DOWNTIME_RESOURCE_CONFIG DR, RATOR_MONITORING_CONFIGURATION.KPI_DEFINITION KD --ON KD.SOAP_SERVICE_ID = DR.DOWNTIME_RESOURCE_ID 
  , RATOR_MONITORING_CONFIGURATION.DOWNTIME_CONFIG DS --ON DR.DOWNTIME_CONFIG_ID = DS.DOWNTIME_CONFIG_ID 
  , RATOR_MONITORING_CONFIGURATION.DOWNTIME_SCHEDULE DTS --ON DTS.DOWNTIME_CONFIG_ID = DS.DOWNTIME_CONFIG_ID
  WHERE DTS.SCHEDULE_RUNNING = 'N' and KD.KPI_ACTIVE_DOWNTIME = 'N' --and DR.DOWNTIME_RESOURCE_TYPE = 'SOAP_SERVICE' and KD.SOAP_SERVICE_ID IS NOT NULL;
  and DR.DOWNTIME_CONFIG_ID = DS.DOWNTIME_CONFIG_ID
  and DTS.DOWNTIME_CONFIG_ID = DS.DOWNTIME_CONFIG_ID
  and CASE WHEN (DR.DOWNTIME_RESOURCE_TYPE = 'SOAP_SERVICE') THEN KD.SOAP_SERVICE_ID = DR.DOWNTIME_RESOURCE_ID 
           WHEN (DR.DOWNTIME_RESOURCE_TYPE = 'SYSTEM_SQL_CHECK') THEN KD.SYSTEM_SQL_CHECK_ID = DR.DOWNTIME_RESOURCE_ID 
           WHEN (DR.DOWNTIME_RESOURCE_TYPE = 'ENGINE') THEN KD.ENGINE_ID = DR.DOWNTIME_RESOURCE_ID 
           WHEN (DR.DOWNTIME_RESOURCE_TYPE = 'FTP_SFTP_SERVER') THEN KD.FTP_SFTP_SERVER_ID = DR.DOWNTIME_RESOURCE_ID 
            WHEN (DR.DOWNTIME_RESOURCE_TYPE = 'DB_CONNECTION') THEN KD.DB_CONNECTION_ID = DR.DOWNTIME_RESOURCE_ID
      END;
    
end chk_kpi_reactivate_downtime;