I have read from a few sources. And they suggest that America tested secret weapons on Panamanians. During operation just cause. There are reports of cars sliced in half and melted bodies.
Further research doesn't seem to come up with cold hard facts confirming this.
How much truth do you think this holds?
I've never heard these rumours. It would probably help if you listed the sources, then people can talk about their reliability.
Going purely on the current state of laser technology this seems unlikely. For example, here's a video from the US Navy in 2011 showing the effectiveness of a laser weapon. Nothing close to slicing a car in half. Here's a 2013 press release from Boeing about their Advanced Tactical Laser, an air-to-ground system. Boeing are happy that it "put a hole in a fender." And here's an article about the first laser weapon to be deployed. The results are more impressive but that's mainly because it seems to have targeted a bomb.
Laser weapons are only now starting to be deployed. A battlefield test in Panama suggests they were close to deployment in the 1980s. We know the US military was seriously interested in lasers in the 80s, but as part of the Star Wars programme. This role hitting small, fast moving targets is still the main focus of development. It's hard to see what would be gained by testing laser weapons in Panama.
Here's an article about the history of laser weapons that might be useful to provide some context.
I would be interested to here your sources. I've never heard of this before