Who Killed an Iranian Nuclear Expert? Israel Isn't Telling (Time.com)

Like three previous Iranian scientists ambushed on their morning commute, the latest nuclear expert to die on his way to work was a victim of Israel's Mossad, Western intelligence sources tell TIME. Mostafa Ahmadi-Roshan, an expert on a phase of uranium enrichment, perished on a Tehran street on Wednesday after an assassin in a passing motorcycle attached a magnetized explosive to the side of his Peugeot 405. "Yeah, one more," a senior Israeli official said with a smile. "I don't feel sad for him."

Wednesday's attack followed the pattern of previous operations planned by Mossad and carried out over the past two years by Iranians trained and paid by Israel's spy agency, according to intelligence sources. The targets were chosen from the ranks of scientists seen as crucial to Iran's nuclear effort -- the country's top physicist, Majid Shahriari, was killed by a magnetized bomb in October 2010 -- then shadowed for weeks to determine their routines and points of vulnerability. (PHOTOS: 60 Years of Israel)

A year ago, Iranian television broadcast the confession of one alleged agent who described studying a scale model of the home of the scientist he helped assassinate by hiding a bomb on a motorcycle outside the front door. "It was the exact copy of the real one, even the size, material, its color, the tree next to it, its asphalt, the street curb, the bridge," said Majid Jamali Fashi on the air. He said he viewed the model in Mossad's headquarters in Tel Aviv, which he described in detail. Intelligence sources confirmed Fashi's involvement in a Mossad cell that the sources claim was revealed to Iran by a third country.

Fashi was sentenced to death for his role in the killing of nuclear physicist Massoud Ali Mohammadi, who suffered mortal shrapnel wounds in front of his house on Jan. 12, 2010. Three other nuclear scientists heard magnetic bombs snap onto their car doors during their commute to work -- a method Fashi claimed he had also been taught by the Israelis. Besides Ahmadi-Roshan and Shahriari, the victims include Fereydoon Abbasi, a university professor who survived and was promoted to head of the Atomic Energy Organization of Iran. (PHOTOS: Terror in Tehran)

A fourth scientist, Darush Rezaei-Nejad, was killed outside his home by shots fired from a motorcycle on July 23, 2011. A student of electrical engineering, his connection to the Iranian nuclear program remains a matter of dispute.

The similarities among the attacks were not lost on Iranian authorities, who immediately blamed both Israel and the U.S. for Wednesday's attack. "The bomb was a magnetic one and the same as the ones previously used for the assassination of the scientists and is the work of the Zionists," Tehran's Deputy Governor Safar Ali Baratlou was quoted as saying by the Fars News Agency.

Israel is officially silent on the incident. However, its top spokesman for the country's military posted this on Facebook: "Don't know who settled the score with the Iranian scientist, but for sure I am not shedding a tear." The Obama Administration insisted it had nothing to do with the attack. "The United States had absolutely nothing to do with this," National Security Council spokesman Tommy Vietor declared. Secretary of State Hillary Clinton made her denial of U.S. involvement "categorical." (LIST: Top 10 Players in Iran's Power Struggle)

The contrast in responses reflects the good-cop, bad-cop roles the allies have assumed in the international effort to dissuade Iran from pushing ahead with its nuclear program. While Washington leads the global effort to press economic sanctions on Tehran, Israeli leaders frequently make thinly veiled suggestions that it may not be able to restrain itself from launching military action on Iran; they also never bother to deny a leading role in covert efforts to slow the nuclear program. In addition to the assassination campaign, Western intelligence sources say Israel was responsible for the massive explosion at a missile base outside Tehran in November.

In an interview published in a Hebrew-language newspaper on Thursday, however, the U.S. ambassador to Israel took pains to portray Washington and Jerusalem in sync on the need for action. The interview was framed by news that Iran was beginning to enrich uranium in a new facility outside Qom, built under a rock shield 200-ft. (60 m) thick. "We see eye to eye with Israel regarding the severity of the threat and the importance of preventing Iran from becoming a nuclear country," U.S. Ambassador Dan Shapiro was quoted as telling Ben Caspit in Ma'ariv. "President Obama has consistently stated that he will prevent Iran from acquiring nuclear weapons, and he means every word. The best way to do this, and everybody agrees, including Israel and the United States and Europe, is through economic sanctions. We need to show the Iranian government that it must choose between the nuclear plan and the country's economic existence. We've increased the sanction to an unprecedented degree, and the pressure will rise even more in the future. We haven't yet achieved our goals, that much is clear, and the news today about the enrichment of uranium at the site near Qom proves that. Iran has further breached its international obligations in a very serious way." (PHOTOS: Protesting Iran's Election Around the World)

And if the sanctions don't work?

"Because stopping a nuclear Iran is so important, we've said this before and I'm saying it again, all options are open. All the possibilities." said Shapiro. "And I'll say more than that, we are examining these possibilities actively, and we are drawing up the necessary plans to ensure that all these options exist, and I'm not ruling out any option. President Obama has clearly said that he will do everything and take every necessary step to prevent Iran from producing nuclear weapons, and I don't think that it has anything to do with the timing of the elections or any other political issue, it's important to a lot of these issues."

Caspit said he asked the ambassador what he meant by "planning the options," and whether they are also training for the implementation of these options, as foreign reports say the Israeli air force has been doing for some time. "Shapiro was quiet, and then said that America doesn't need all that much training: 'We have a massive military presence in the Persian Gulf, right?'"

PHOTOS: TIME's Pictures of the Week

SPECIAL: TIME's 2011 Person of the Year: The Protester

View this article on Time.com

Most Popular on Time.com:

Source: http://us.rd.yahoo.com/dailynews/rss/world/*http%3A//news.yahoo.com/s/time/20120113/wl_time/08599210437200

nbc sports bengals vs texans nfl playoffs cincinnati bengals bengals the stand josh mcdaniels