at first glams, melaku seems to fit the profile. >> how can we empower local law enforcement in particularprevent a lone wolf from being successful. >> reporter: those fears have been heightened in the wake of osama bin laden's death, leaving security officials and americans on alert, wondering if the terrorist threat is heating up this summer. >> right now, al qaeda wants to be able to demonstrate that they are a force to be reckoned with. >> reporter: and in the weeks since the raid that killed bin laden, there are signs that al qaeda is more determined than ever to attack america. adam gadahn, al qaeda spokesman, released this new video, challenging american muslims to take up arms against their own countrie countries. >> muslims have s in the west remember they are in perfect place. >> reporter: al qaeda officially announced this week they have a new leader. this is him in egyptian prison years ago. >> we want to speak to the whole world. >> reporter: osama bin laden's closest adviser. the latest threat, train derailments. journals found in osama bin laden's compound contained evidence

royal newlyweds william and kate got glammed up for their first public night out. >> the duke and duchessblack tie charity banquet at kensington palace. last night. prince william announced the funds raised would transform lives of thousands in the u.k. and africa. >> boy is she thin, extremely thin in that dress. my goodness. they had a healthy head start. tickets were $16,000 apiece. why not though. >> lots of glam. >> fun night for wills and kate. they look great. >>> extreme heat has been baking the big apple and rest of the northeast. finally broken a little bit. we had incredible weather yesterday. big black eyed peas concert in central park. canceled. thunder, lightning, hail. >> like the fever has broken. it only cleared, after record highs. thermometer in newark, 101 yesterday. d.c., 102. philadelphia, just 99. some schools closed early. while others canceled classes altogether. the heat wave blamed for at least seven deaths from the plains to the east coast. with some serious stuff. >> dangerous heat. taking a look at your weather. coming up. up to about 20 degrees cooler in the