You access the Rooftops by grappling up the the building to the right of the Grease Monkey garage. Then you can grapple to buildings farther left. Because there is a guard, and there are lasers that block the grapple, you cannot directly reach the top of the tallest building. Instead, go farther left to the red building, and climb that one. At the top, you can grapple right to get to the tower. (A friendly spy suggests this.) Enter the tube to rescue the third spy from the Greenhouse.
keep going up than to the left
There is a ladder and all you have to do is jump up it.
On top of the building above Dr. Spy Glass's shop. (you have to hop on the wire to get up there.)
either in the building with all the Venus fly trap in the cage or in the building tied up in the in the attic
The path to reach the third spy on Spy Island goes left from the Rooftops above the Grease Monkey garage. There is a guard who will attack you on the middle building, and no way to go straight up. So you go left to the reddish building and climb up. At the top, a helpful spy will suggest using the Grapple Bowtie to reach the tall antenna back to the right (atop the target building).
Once you get the bow-tie that swings you every where, you use that to swing to another building! get to the highest building you can and search for buildings up on the roof with the bow-tie! I hope this helped!
He is in the building on Toupee Terrace that zaps you with its electrified windows. To rescue the second spy, jump up the windows while the power is off (it takes timing). At the top, use the Laser Pen from the first spy to cut open the bars.
To rescue the second spy, avoid the electrified windows. To rescue the third spy, you will need to go up one building to the rooftops, then to the far left and back again. This requires the Grappling Bowtie from the second spy. (see the related question)
You don't have to there is not a comic up there!
On Balding Avenue, climb the building to the right of the Grease Monkey garage. Enter the "Rooftops". Put on your chameleon suit and grapple left, to the guarded building. Grapple left again, then up, and back right from the top of the red building (there is a friendly spy there).
Yes, but via the roof. The large, reddish*, church-like building on Toupee Terrace is the location of the SECOND missing spy. It has electrified windows that turn on and off at a regular interval. Rather than entering, you do have to climb up the outside. The rescue of the FIRST spy (at the docks) provides the Laser Pen to cut through the metal bars on the building's attic window. (see related question) * There is another "red" building, the first one (left side) on Balding Avenue. This is the one referred to in the use of the Grappling Bowtie supplied by the second spy.
Use the Chameleon Suit to elude the guard, and continue farther left to the red building, where you can climb up to the tower. Once you are high enough, grapple back to the right to reach the other antenna. A friendly spy there will suggest this.