Blood splattered in the Flatbush apartment where pregnant bride-to-be Vindalee Smith was found slashed to death may have come from more than one person — and a bloody fingerprint was found on an envelope with a note next to the body, sources said.

Cops are conducting DNA and fingerprint analysis of the evidence found in Smith’s apartment on Saturday — a day before her wedding to Anthony Jackman, who sources said “put himself at the location” of the murder.

The note said, “I will kill 1 pregnant woman a month starting now until Lee Boyd Malvo [the Washington, DC, sniper] is set FREE.”