The widow of a school-bus driver killed during an undercover NYPD bust-gone-bad plans to file a $20 million wrongful-death suit against the city.

Wanda Spruill-Kumi is suing for the “wrongful death” of Felix Kumi, 61, on Aug. 29, 2015, when he was hit by a stray bullet as he unknowingly walked across a Mount Vernon street during an undercover gun purchase.

When the sale went bad, an undercover cop unleashed a torrent of bullets at 4 p.m. on the quiet suburban street, striking and killing Kumi, the suit says.

“The notice of claim is being reviewed,” said a city Law Department spokesman.