The present invention relates to a mediation function node in a Lawful Intercept system and a method (S100) in a Lawful Intercept system for enabling a Law Enforcement Agency, LEA, to determine targets' positions. Said targets are connected to a WiFi network via an Access Point. The method comprises steps of: —receiving (S110) a RADIUS account message for a subscriber having been accepted access to the WiFi network; —retrieving (S120) from the received RADIUS account message RADIUS parameters corresponding to an Access Point Identifier and a Service Set Identifier, SSID, if the subscriber is a target; —sending (S130) together with a target identification the RADIUS parameters corresponding to the Access Point Identifier and the SSID to the LEA.