A computer-implemented method comprising: detecting an alarm event at a monitored property based on output from at least one sensor located at the monitored property; in response to detecting the alarm event at the monitored property, initiating a process to gather electronic identifiers for mobile electronic devices located within the monitored property at a time corresponding to the detected alarm event; based on the process to gather electronic identifiers for mobile electronic devices located within the monitored property at a time of the detected alarm event, determining electronic identifiers for the mobile electronic devices located within the monitored property at a time corresponding to the detected alarm event; storing, in electronic storage, information indicating the determined electronic identifiers for the mobile electronic devices located within the monitored property at a time corresponding to the detected alarm event; analyzing a log of electronic device information to determine certain information about the monitored property, wherein analyzing the log of electronic device information comprises triggering, in response to the alarm event, electronic device detectors, wherein the electronic device detectors are also configured to continuously or periodically track identifying information of devices located within the property, monitoring by the electronic device detectors for electronic devices and recording identifying information received from the detected devices in the log, and sending, in response to the alarm event, data in the log from a monitor control unit to a monitoring application server, and comparing the log of electronic device information against electronic device identifiers detected during an alarm event in an attempt to determine whether the electronic devices detected during the alarm event have been in the monitored property previously and when they were in the monitored property; and if the comparison reveals that one or more of the electronic devices detected during the alarm event were previously in the property, a report is generated to show when the one or more electronic devices were in the property. detecting an alarm event at a monitored property based on output from at least one sensor located at the monitored property; in response to detecting the alarm event at the monitored property, initiating a process to gather electronic identifiers for mobile electronic devices located within the monitored property at a time corresponding to the detected alarm event; based on the process to gather electronic identifiers for mobile electronic devices located within the monitored property at a time of the detected alarm event, determining electronic identifiers for the mobile electronic devices located within the monitored property at a time corresponding to the detected alarm event; storing, in electronic storage, information indicating the determined electronic identifiers for the mobile electronic devices located within the monitored property at a time corresponding to the detected alarm event; analyzing a log of electronic device information to determine certain information about the monitored property, wherein analyzing the log of electronic device information comprises triggering, in response to the alarm event, electronic device detectors, wherein the electronic device detectors are also configured to continuously or periodically track identifying information of devices located within the property, monitoring by the electronic device detectors for electronic devices and recording identifying information received from the detected devices in the log, and sending, in response to the alarm event, data in the log from a monitor control unit to a monitoring application server, and triggering, in response to the alarm event, electronic device detectors, wherein the electronic device detectors are also configured to continuously or periodically track identifying information of devices located within the property, monitoring by the electronic device detectors for electronic devices and recording identifying information received from the detected devices in the log, and sending, in response to the alarm event, data in the log from a monitor control unit to a monitoring application server, and comparing the log of electronic device information against electronic device identifiers detected during an alarm event in an attempt to determine whether the electronic devices detected during the alarm event have been in the monitored property previously and when they were in the monitored property; and if the comparison reveals that one or more of the electronic devices detected during the alarm event were previously in the property, a report is generated to show when the one or more electronic devices were in the property.