David Superville, who beat a murder charge after experts found that North Miami Beach police forged his signature on a key court document, died last week after an unexpected diagnosis of luekemia.

His death adds a sad twist to a bizarre love triangle murder case that also included the lead detective romancing Superville’s ex-wife.

Superville, 50, had been healthy and working as a used car salesman. But last week, he checked into a hospital after feeling ill. He was diagnosed with leukemia, and by Saturday had died of complications.

“While David died knowing that his name had been cleared, I’m still troubled that his life was destroyed by this police investigation,” said his attorney, Andrew Reir. “His case should have never been filed. He lost his wife. He lost his business. He was left with nothing.”

Police arrested Superville in 2007 on allegations he helped set up the assasination of Eduardo Duarte, gunned down six years earlier in North Miami Beach. The suspected mastermind was Ivan Amaral, a Brazilian businessman who allegedly targeted Duarte because he had dated Amaral’s former girlfriend.

Investigators said Amaral paid Superville to surveil the man’s daily routine, and provided the getaway vehicle, the gun and a homemade silencer to the hitman. Superville claimed he was an amateur private eye who never knew Duarte was going to murdered.

The case’s lead detective, Ed Hill, later began a romance with Anna Gulevitskaya, a so-called Russian mail-order bride Superville met through the Internet and brought to the United States. North Miami Beach police suspended Hill for three weeks over the affair.

Then last year, Superville’s defense team alleged that Hill forged Superville’s signature on a March 2007 Miranda rights waiver form, which is supposed to be signed by a suspect before giving a formal police statement.

A expert hired by prosecutors agreed that the form was a fake and the murder case was dropped. Prosecutors did not charge Hill, saying they could not prove who forged the signature, and the veteran detective resigned and gave up his police credentials.