This is "Dark Angel" from 1990.
The blurb mentions that it's basically a police procedural but with aliens.
The other alien that has landed on Earth is a lawman and was sent to
track the drug dealer. He will need Lundgren's and Benben's help to
catch him. Throw in the fact that the alien drug dealer takes on drug
dealers on Earth and you have non stop action.
This review mentions a strange alien CD-like projectile caught on a speaker magnet
This is one of the scariest and funniest movies Dolph Lundgren ever
did. I enjoy it immensely and I'm disappointed to see it so expensive
and hard to get. I hope a Blu-ray version comes out as this movie did
not get the exposure it should have during it's release Christmas of
1990. I am kind of surprised so few have heard of this SciFi with aliens coming to Earth. Police detectives Lundgren and Benben try to
figure out what exactly they are doing after some drug dealers and
civilians are murdered. At a drug dealers they find several dead
bodies and a unusual sharp metal CD stuck to a speaker magnet. The guy
they take it to for analysis at the university looks like he has been
drinking Jolt and taking amphetamines. The whole movie has a mix of
good SciFi drama and comedy. I had never seen Lundgren in a comedy
before and this was a nice change of pace. It reminds me of how
"Twins" made a difference in Arnold Scwharzenegger's career. Great
quality DVD with plenty of replayability. If you enjoyed this, catch
Split Second.