Leak in 03 lincoln

Everytime it rains, the back seat floor mats are soaked! The car is an 03 Lincoln Town Car and no one can seem to figure out where the leak is coming from…does anyone have any suggestions? If I drape a canvas over the trunk and the back window, the floor mats do not seem to get wet yet there is no water in the trunk when the mats get soaked. I am at my wits end and ready to get rid of the car if it cannot be fixed.

Does your Town Car have a moon roof?
If so, there are drain hoses that run down from all four corners of the roof. One of the two rear ones may have become disconnected. This is not an unheard of problem.

Floor mats or carpet gets wet? Tardis is probably has this, but if you are talking about the passenger side rear carpet, there is a TSB for this.

IIRC, the defect is in the seal around the fresh air intake. The drains in the drain tray under the windshield and windshield wipers tend to clog up filling it with water. It then seeps into the fresh air intake and into the car via the passenger footwell. The water can appear in the rear if the car is parked on a slope.