HI Carlos,
You need to shutdown the CA SAM Integration service on the APM connector machine. Once the connector is offline go to the SOIUI\Administration\Connector Configuration, select the APM connector (it should show offline now) and click on the "Remove Connector" button, this'll remove all CIs and alerts published from the APM connector. If it gets removed successfully start the CA SAM Integration Service. if you fail to remove the connector the way I mentioned then you'll have to use the soittolbox to remove the connector and its related data.
Let me know if you have any question.
Thanks
Shaheen