A computer-implemented method comprises: receiving (100) first information indicative of a tracking device being located in a particular place, for example by detecting that the tracking device is connected to a charging station for charging； receiving (102) second information, from a passive detecting means, indicative of the user of the tracking device leaving said place, for example based on sounds that the user has made in leaving； (104) determining, based on the first and second information, that a user of the tracking device leaves said place while the tracking device remains in said place； further to said determining, causing (106) at least one separation related action to be performed, for example sending a message to a remote server (14).
