def retrieve_agent_profile_ids(self, agent, since=None):
        """Retrieve agent profile id(s) with the specified parameters

        :param agent: Agent object of desired agent profiles
        :type agent: :class:`tincan.agent.Agent`
        :param since: Retrieve agent profile id's since this time
        :type since: str | unicode
        :return: LRS Response object with list of retrieved agent profile id's as content
        :rtype: :class:`tincan.lrs_response.LRSResponse`
        """
        if not isinstance(agent, Agent):
            agent = Agent(agent)

        request = HTTPRequest(
            method="GET",
            resource="agents/profile"
        )
        request.query_params["agent"] = agent.to_json(self.version)

        if since is not None:
            request.query_params["since"] = since

        lrs_response = self._send_request(request)

        if lrs_response.success:
            lrs_response.content = json.loads(lrs_response.data)

        return lrs_response