john farahs, cnn washington. >> we have been reporting that there is a lot of police activity in revere, massachusetts. that is not far from boston. about five miles. >> brian todd is there. he joins us on the line now. what are you seeing? >> we were told by a massachusetts state police official there that they were checking out one apartment in the building. police were there for several hours. there were massachusetts state police and revere police there. a neighborhood told us they had been there since at least 5:30. they left, we believe, the last of the police officials left at about 2:00 in the morning. so, we, you know, we were there outside the building pretty much the whole time. they would not talk to us and tell us exactly what they were doing there. two gentlemen came in who they did question. that's about all we can tell you. that's what we saw through the lobby. and they were checking out one apartment. but whether this is a heart connection to the case we're not sure right now. >> do we know exactly what they are looking for? this suspect if this is actually a solid lead