Unusual events begin to plague a modern fitness center in Southern California, unsettling the owner, William Bumiller, and prompting a police inquiry. The possible causes seem to be his difficult former brother-in-law, Merritt Butrick, disgruntled staff members, or perhaps the disturbed spirit of his deceased wife. "Death Spa," released in 1988, surpasses "Killer Workout" from the year before and should appeal to …