A method and system for determining a suspected data source among one or more data sources reporting geo coordinate data in a location based services network is disclosed. In some embodiments, the method includes, receiving geo coordinates of a user device reported by the one or more data sources over a period of time, calculating a notional speed between geo coordinates reported at two consecutive times, flagging simultaneously, one or more data sources that reported the geo coordinates at the two consecutive times resulting in a notional speed that exceeds a predefined notional speed, and analysing a data on at least one of, the number of instances of geo coordinates reported by a data source, the number of instances a data source was flagged, the data sources that were also flagged simultaneously with each flagging, for determining the suspect source of data.