Searching for Cheryl

 refers to an unmarked quest in Fallout 3.

Walkthrough
Follow the trail of a party who went out to find Cheryl, sister of the party leader.

First log
In L'Enfant South you can find a burial mound containing Search Party Log #1. When exiting the metro turn right and the grave is in front of the last house on the right side of the street.

Second log
As mentioned in the first log, go to the Ranger Compound and access the outdoor terminal to read about the Canterbury Search Party. The terminal can either be unlocked by Reilly or is a very hard hack.

Third log
The "Western Ruins" mentioned in the second log are located to the north of Potomac Bridge, below a raider camp. The Search Party Log #3 is in a second burial mound there. To get to that raider camp, travel to Dukov's Place go south towards the Potomac Bridge (the only bridge over the big river for miles). Between the raider camp and the bridge you can find the grave.

Last log
Search Party Log #4 is in a grave directly northwest of the Sewer Waystation. To find the grave, walk toward a big Corvega billboard (which may have an Enclave poster stamped on it if you have completed the Waters of Life quest). The grave is to the left of and before you get to the billboard, in front of the fence, on the northeast side of some rocks.

Find Manny
A short distance west southwest of Jury Street Metro Station you run into a group of super mutants hiding out near a small wrecked train. Entering the container with the shopping cart cages and taking the teddy bear in it causes a super mutant behemoth to appear (this may take a while, as he runs toward you from a distance). In this camp you can find the corpse of Manny Koch, leader of the search party. Apart from the loot on his body the main reward is a mini nuke on the behemoth.

Reward

 * Mini nuke
 * Various other loot

Bugs

 * Manny Koch may be quite alive and very hostile to the player if the super mutant camp was cleared prior to progressing through the quest and meeting him there. The behemoth trigger doesn't need to be activated. In this case the player has no choice but to defend himself/herself against the woefully under-equipped Manny. His body may be glitched (360 no patch), either distorting in space, or falling into pieces then reforming. If he grabs a weapon, this one may become invisible. If killed he will drop a finger (with the lawbringer perk). (Xbox 360 confirmed)
 * Sometimes Manny Koch will not spawn. The only bodies in the area will be the burned skeletal remains by the shopping carts.
 * The behemoth might not spawn when you take the teddy bear out of the cage. Next time you fast travel to Jury Street Station he should be standing there down the street though.