The Washington Post reports: The assassination Wednesday of an Iranian nuclear scientist in northern Tehran increases the peril for an Iranian American who was sentenced to death Monday, analysts said.

Iranian officials quickly blamed the scientist’s killing on the United States, ratcheting up tensions between the two countries and making it less likely that Amir Mirzaei Hekmati, a 28-year-old former U.S. Marine arrested in August and accused of spying for the CIA, will be released anytime soon.

“Unfortunately, the greater the escalation is, the greater the likelihood that the perceived costs of executing him decline,” said Trita Parsi, president of the National Iranian American Council and author of a new book about the Obama administration’s dealings with Iran.

In recent years, there has been an increase in mysterious explosions at military and industrial sites in Iran. Three scientists involved in Iran’s nuclear program have been assassinated, and a computer virus called Stuxnet wreaked havoc on the program.

As Tehran faces tighter international sanctions, a faltering economy and continued scrutiny of its nuclear program, the country’s justice system has turned its attention to Iranian Americans.

There has been a string of arrests of dual nationals in recent years. Typically, Iran charges them with espionage and sometimes shows them on state-run television making “confessions,” under what the detainees later say was duress. Negotiations have usually led to the detainees’ release after several months, sometimes after the announcement of a lengthy prison sentence.

But even analysts who believe Hekmati is being used as a bargaining chip say they were taken aback by the swiftness and harshness of his sentence.

The U.S. government, which does not have diplomatic relations with Iran, has said that Hekmati is not a spy. The CIA has declined to comment on the case, but Art Keller, a former CIA case officer, said Hekmati does not fit the profile of an undercover agent.

“I have a hard time believing that we would send someone over under his true name with his military affiliation well known,” he said. “That’s what you have alias documents for.”