MADRID — An American man accused of killing a jewelry store owner in the U.S. and stealing $300,000 (€228,000) in diamonds before fleeing to Europe was found hanged in his prison cell in Spain, authorities said.

Andrew Robert Levene was found dead Thursday in the Modelo prison in the northeastern city of Barcelona, where he was recently arrested after an international manhunt, the justice department of Catalonia said.

An investigation into the death was under way but all signs indicated he had committed suicide by hanging himself with a sheet, a spokeswoman said.

Levene, 41, was charged with federal murder, robbery and firearm offenses in the Dec. 8 shooting of Yekutiel Zeevi, owner of YZ Manufacturers LLC store in Westport, Connecticut. Extradition proceedings in Spain had not yet begun.

The justice department spokeswoman said that as with all people admitted to prison, Levine had been interviewed by prison authorities and showed no signs that he might do himself harm.

She spoke on condition of anonymity in keeping with department regulations.

Levene contacted Zeevi in early December, asking him for several diamonds that were valued between $45,000 and $75,000, U.S. authorities said.

The evening before the shooting, Zeevi met Levene, who examined the diamonds and was noncommittal about buying them, authorities said.

Levene met with Zeevi again on Dec. 8 on the ruse that he would buy several large diamonds. Instead, Levene shot and killed Zeevi, authorities said.

Levene, who had military training in the use of weapons, stole about $300,000 in diamonds, authorities said.

Ronen Konfino, an executive at a New York diamond business, also was shot but survived and helped police with the investigation.

Levene traveled to Amsterdam from Philadelphia on Dec. 11 after missing a flight to Madrid, law enforcement officials said. Police said in mid-December that Levene had been seen in Philadelphia, possibly casing stores.

It was not immediately known why he had traveled to Barcelona or when he had arrived there.

U.S. Embassy officials in Madrid said Thursday they were notified that Levene, also known as Robert Thomas, had died but could give no further details.