Rear Window Investigation

A character, usually female, suspects a male character, often a neighbor, of committing a crime. Perhaps she is even a witness of the crime. Nobody believes her, or she isn't sure herself, so she decides to wait until he leaves his house, and then sneak in to look for clues or to obtain incriminating evidence. Of course, the potential suspect will invariably come home early, and the investigating character will have to find a way out of the house without being discovered. Sometimes they do, sometimes they don't.

This can be an Idiot Plot, because the character in question often fails to be certain that the probable bad guy will actually be gone for a while and is not just getting his mail or something. In some versions, another character will be placed as a lookout, but they will either become distracted and fail to notice the bad guy as he arrives home, or their signal to get out will go unnoticed by the infiltrating character.

There's also a less common but still prevalent comedy version of this trope, where the investigating character is trying to retrieve something, often an embarrassing item they've left behind.

Compare Alone with the Psycho, The Stakeout.

Examples of Rear Window Investigation include:

Film

Alfred Hitchcock's Rear Window, of course. Indeed, many of the following examples are in fact Shout Outs.
Woody Allen's Manhattan Murder Mystery.
Rear Window's Spiritual Successor, Disturbia.
Blue Velvet.
Happens in the French political Thriller I... Comme Icarus
The 'burbs has a comedic version of this trope.
Both Mimic 3: Sentinel and Abominable offer scifi/horror spins on the trope.
Lindsey goes into her sister's murderer's house in The Lovely Bones.

Folklore

This is a crucial part of the English folktale, Mr Fox. Lady Mary, Mr Fox's intended bride, is suspicious of him and follows him home to see his castle for herself - and gets more than she bargains for when she finds the literal skeletons in his cupboards. A ballad version by the folk group Mr Fox has the girl bring home evidence of her encounter with Fox's latest conquest and confront him with it:

Foxy took his knife
And with a blow both sharp and sweet
The hand was severed from the wrist
And dropped down at my feet
...
Foxy turned his back on me
He turned as if to leave
But I took him by the arm and plucked
The hand from out my sleeve

Literature

Occurs in Jane Austen's Northanger Abbey where after reading too many Gothic novels, the heroine begins to mistrust her host General Tilney and suspect him of murdering his wife years before. Given that that this novel predates Rear Window by almost two centuries, it's Older Than Radio.
In Bruce Coville's My Teacher Is an Alien, the narrator breaks into her new teacher's house to look for evidence that he truly is otherworldly. Unfortunately, her lookout had a short attention span. Hilarity Ensues.
In The Lovely Bones a girl breaks into her neighbor's house to look for incriminating evidence in the death of her older sister.

Live Action TV

Are You Afraid of the Dark?? episode "The Tale of the Nightly Neighbors."
The Monk episode "Mr. Monk, Private Eye" contains a unique version of this trope, in which Monk sneaks on to a potential killer's boat and is promptly stowed away.
Done ad nauseum in Psych, wherein Shawn has ended up stowed on a boat, caught sneaking around various facilities (including a Seaworld-like park after-hours), and too many others to count. The sheer number of times he has snuck into someone's property means that, statistically, he should still be paying fines/jailtime for breaking and entering by 2099.
In a Halloween episode of That '70s Show, Fez breaks his leg and stays in Eric's room, watching the Pinciotti's house and hoping to see Midge, their MILFy next door neighbor, naked. However, when she's nowhere to be seen and her husband Bob is seen by Fez carrying a large, bloody bag, Fez immediately assumes that Bob killed Midge. It turns out that Bob had merely butchered a cow and Midge was away on vacation.

Western Animation

The Foster's Home for Imaginary Friends episode "Neighbor Pains", where Bloo has to go into Old Man Rivers house to look for the adoption forms that Rivers took. The papers he brings back turn out not to be the forms, but love letters to Madame Foster, which Mac and Bloo use to blackmail Rivers into giving them the forms.
Parodied in The Simpsons episode "Bart of Darkness". Bart, injured from an accident diving into their swimming pool, overhears a scream from the Flanders house, and witnesses him burying something in the backyard. Believing Ned had murdered his wife Maude, Bart orders Lisa to go investigate. When Ned returns home early, Lisa gets trapped in the attic with Flanders, who is attempting to put away an axe (though from Bart's view it appeared Ned was threatening Lisa with the axe). It later turns out that Maude is alive, and was away at Bible camp the whole time. The scream that Bart heard earlier? It was Flanders.
An episode of Rocko's Modern Life dealt with Rocko thinking Bev Bighead killed her husband Ed so he goes into their house to investigate, as it turns out Ed went to the hospital to remove a wart, the stabbing was Bev making a sculpture of Ed, and she buried a dead plant.
An episode of The Flintstones dealt with their new neighbor apparently killing his nagging wife and Fred and Barney go to investigate; at the end he tells them she went on vacation, but in a subversion he reveals to the audience that he indeed did kill her as he fed her to his wife eating bird.