Second bachelors degree or masters degree?

[sevenanseven]

I have my B.S. degree in psychology, but, many years later, I am now interested in pursuing a career as a forensic scientist (crime lab technician). From what I've researched, I need to have my bachelor's in one of the physical sciences. I'd be most interested in pursuing a degree in physics. What do I do? Do I need to pursue a second bachelor's degree in physics? Or pursue a master's degree? How does this work considering I already have my bachelor's degree.

I'm not exactly sure what I need to do. My bachelor's degree is obviously in the wrong subject for what I need now for my chosen career. Thanks in advance for your help.