"Heather Bloom was last seen in the care by her sister, Shari Bloom, who resides in Berkeley, California. Heather has not been seen since 2005. Heather has down syndrome and may be seen in a wheelchair. Heather is non-verbal and requires constant care and daily medication for a thyroid condition:" NAMUS.
"The police went to Shari's new apartment in March 2010 and she wouldn't open the door for them. She answered questions through the window and said Heather was fine, but she refused to let anyone see Heather or come inside the home:" Charley Project.
Clue: This Man Lost His Left Eye & 3rd/4th Fingers on His Left Hand. How and When Did It Happen? Old Injuries from Work, Military Service or Accident?
He was found unresponsive around 8600 Old Georgetown Road in the Bethesda/Rockville-area of MD and soon died in the hospital during August 1989. See his photo (warning: may be disturbing to some people) and more info here.
Jan '21 Update: They Have Been Identified Via DNA; Their Names Not Yet Released to Public -- Who Murdered this Couple? Was the Man "Jock or Jacques," a French Canadian from a Wealthy Family? The Sumter County (South Carolina) "John and Jane Does." Click
"On August 9, 1976, the bodies of an unidentified white male and white female were discovered on a dirt road 1/2 mile from Interstate 95 and Highway 341 in Northeast Sumter County. The road is known as Locklair Road, a frontage road just off the interstate. Both victims were shot multiple times:" NAMUS. There are many clues to their identities, including the initials "JPF" on the man's ring ("J" for "Jacques" or "Jock?"), witnesses who met and saw them before their killings and their good health and professional dental work (likely done abroad for the man). Yet they remain unidentified decades later. BTW, DNA testing determined they were not, contrary to speculation, siblings.
More detail and post-mortem photos of the couple can be found here.
Resources: Missing Persons List + Search Missing Persons by State + Unidentified Remains
NAMUS: Federal government database for missing, unidentified and unclaimed people. The “official source” used by law enforcement. Allows you to track cases. https://www.namus.gov/
Charley Project: Missing persons database with good detail on cases. https://charleyproject.org/
Doe Network: Current missing persons cases and unidentified remains. Includes international cases. http://www.doenetwork.org
Missing Veterans: Detailed profiles of missing veterans. http://www.missingveterans.com