Robert Picardo -- who played The Doctor on "Star Trek: Voyager" -- got more fireworks than he bargained for July 4 ... cops are investigating a domestic violence incident at his home.
Law enforcement sources tell us ... cops went to Picardo's residence Friday night after someone in the house called 911 ... then hung up. We're told officers interviewed Picardo and his wife, Linda Pawlik ... who claimed he hurt her during a fight ... he denied it and no arrests were made.
Picardo filed for divorce from Pawlik back in 2012 but the case went nowhere until May ... when Picardo hired a new lawyer.
A source close to the couple tells us ... the divorce is definitely on and every once in a while things get a little heated.