It could be his greatest escape yet.

The body of John Dillinger — the infamous bank robber who twice escaped from jail — will be exhumed from an Indianapolis grave, although it’s not clear why.

The Indiana State Department of Health approved a permit on July 3 for the 1930s gangster’s nephew, Michael Thompson, to dig the remains out from under a massive concrete tomb at the Crown Hill Cemetery — only to put them back into the ground the same day.

The permit does not indicate a reason for the exhumation, and the cemetery could not provide further details.

Health department spokeswoman Jeni O’Malley said Dillinger’s bones will be dug up and reinterred Sept. 16.

Dillinger’s great-nephew Travis Thompson told the IndyStar on Tuesday that the family declined to comment on the plan.

Unearthing the notorious convict could be a heavy lift — Dillinger’s dad had the casket buried under a series of concrete slabs to thwart grave robbers.

“I think they’re going to have a hard time getting through that,” Susan Sutton of the Indiana Historical Society said.

The Indianapolis-born Dillinger and his gang killed 10 people as they knocked over Midwest banks and engaged in other crime. Dillinger also was notorious for his Houdini-level ability to break out of jail.

His first escape came in 1933, after he was arrested for robbing a bank while out on parole, according to the FBI.

While cops were frisking him, they found a document planning a prison break. He claimed ignorance, but four days later, eight of his pals busted out of Indiana State Prison using the same plans.

Less than a month later, three of the escapees busted Dillinger out of jail in Lima, Ohio, by pretending to be correction officers seeking to transport Dillinger.

Following the escape, they fatally shot a sheriff and Dillinger got away.

He was picked up again in 1934 for the killing of an East Chicago police officer, but managed to bluff his way out of the “escape proof” county jail in Crown Point, Ind., by whittling a fake gun out of wood and using it to cow guards into his cell, which he locked before bolting, according the FBI.

Dillinger was fatally gunned down by FBI agents on July 22, 1934, as he tried to flee lawmen.

With Wires