Pics Show House Interior Where Man Was Allegedly Held by Stepmother for Decades

A woman allegedly held her stepson captive for more than two decades in Connecticut ... and creepy new photos capture the inside of the badly burned residence.

Kimberly Sullivan's house -- where prosecutors allege she kept her 32-year-old stepson, identified only as "S," captive for years -- is a blackened mess after "S" allegedly burned the place down in order to escape.

A half-melted Marilyn Monroe poster sits on a table in one room ... while bare beams are completely exposed ... all the drywall and wallpaper burned away.

One room appears somewhat untouched ... a hot-pink sitting area on the first floor with an unsettling doll hanging from strings in the corner, surveying the area. Painted on one wall are two smoky eyes and seductive pink lips

A pair of lacy angel wings are nailed to the wall in what looks like an attic ... the room where "S" allegedly spent years. A trunk with unknown items in it sits in the corner of a dark room.

Firefighters found "S" earlier this year ... weighing just 68 pounds and covered in filth after authorities say he lit the home on fire.

He's alleged his stepmother kept him captive in an 8-by-9 foot storage space ... claiming Kimberly took him out of school when he was just a child and gave him only scraps of food and water. Sullivan was arrested several weeks after "S" set the fire.

Sullivan has denied all the claims against her ... and her lawyer has said it was actually her late husband -- the father of "S" -- who kept him locked up until he passed away last year.

According to the New York Post, Kimberly Sullivan is expected back in court on Halloween.