Even Congress website isn’t sure about the date of death:

• 29th: https://bioguide.congress.gov/search/bio/F000062

• 28th: https://www.senate.gov/senators/SenatorsDiedinOffice.htm

… and the last one who died in the office was: NoName.

I bet the real date is … 27th.

EDIT: They’ve changed 28 to 29 now.

Even Congress website isn’t sure about the date of death:

• 29th: https://bioguide.congress.gov/search/bio/F000062

• 28th: https://www.senate.gov/senators/SenatorsDiedinOffice.htm

… and the last one who died in the office was: NoName.

I bet the real date is … 27th.