Updated and solved...Door lock Trimark 30-1050/030-2650

They are easy to take apart. If the dead bolt works it is the latch itself that probably broke. Once you remove the screws you can see the inside and will probably find the latch in two pieces. Some people on here have actually had that latch machined out of steel by a local machine shop which will last forever. The other thing that fails is the white plastic cam actuator that actually opens the latch when you pull on the handle. My guess it is the latch itself.