8:31 AM PT -- Prosecutors say Crawford's victim is a 12-year-old girl.

Officials say Crawford's wife caught the football star in a sexual situation with the victim around 5 AM on Saturday morning.

When pressed by investigators, officials say Crawford eventually admitted having sexual intercourse and oral sex with the girl -- and said it was her idea.

The girl told investigators she was asleep in the living room when Crawford began to sexually assault her.

A rape kit was later administered on the girl.

Crawford is currently behind bars -- being held without bond.

Justin Crawford -- the former West Virginia star running back -- has been arrested in Georgia on some pretty disgusting charges, TMZ Sports has learned.

Officials confirm ... the 23-year-old is facing charges of incest, child molestation sodomy and enticing a child for indecent purpose, all felonies.

Details surrounding the allegations are unclear at this point, we're working on it.

What we know ... Crawford was taken into custody on Saturday and booked. We've obtained his mug shot.

Crawford was a huge junior college star before transferring to West Virginia after the 2015 season. In fact, he was the 2015 national junior college player of the year.

While at WVU, he racked up two 1,000 yard rushing seasons in a row -- but didn't get drafted.

He was later signed as an undrafted free agent by the Atlanta Falcons in 2018 -- but was cut in September after a poor showing in several preseason games.