Argosy University has a post grad cert in Forensic Psychology that might work for you. C - Forensic Psychology Certificate - Schaumburg - Argosy University
The University of North Dakota (University of North Dakota) offers an online Master of Arts in Forensic Psychology.
Here's a program that's "close" to Forensic Psychology... University of Massachusetts Lowell offers an Online Graduate Certificate Program in Forensic Criminology The Graduate Online Certificate in Forensic Criminology
I say this to everyone that mentions forensic psychology so don't be offended. Before you get your heart set on forensic psychology, research what forensic psychologists do. People think they're going to make criminal profiles for the FBI and going on manhunts. It's not like it is on TV. It's unlikely you'll be Dr. Sweets from Bones. It's a lot more clinical assessments and testifying in court that someone needs to be committed. So if that's what you want to do, this is the field for you.
I'd also like to note that most Forensic Psychologists used by state & federal agencies have clinical doctorates and additional background in forensics and law. But back to the question at hand, the Chicago School has an online cert, but they want 5 years of background for entry.
Being that you are in Texas, if you are seriously considering a career in forensic psychology, I'd throw out there that Sam Houston in Huntsville (B&M) has an excellent program for this.