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In the latest twist to theenigmatic case of kidnapped American journalist Daniel Pearl, police investigators rushed to a hospital in this port city early Monday only to find that a body brought there with a bullet wound in the head was not that of the U.S. reporter.

The body had been dumped in an old quarter of the sprawling, crime-ridden city and was brought to a public hospital, then transferred to a private hospital.

Summoned to the clinic, investigators and close colleagues of Pearl from the Wall Street Journal ruled out the possibility that the body was Pearl’s, based on its smaller stature, darker complexion and different teeth, according to Manzoor Mughal, senior superintendent of police in Karachi.

“It wasn’t even a close match,” U.S. Consulate spokesman Lonnie Kelley said.

The body was believed to be that of a foreign male, possibly an Iranian, Mughal said.

“There was a threat that kidnappers were going to dump [Pearl’s] body,” said Tariq Jamil, deputy superintendent of police in Karachi. “That’s why we take these reports seriously.”

The development marked the second time in three days that those closest to the case feared that Pearl, who disappeared here Jan. 23, might be dead. On Friday, Western news organizations received an e-mail–at the time believed to be from the kidnappers–declaring that Pearl had been killed and his body dumped in one of the city’s graveyards.

As the latest scare passed early Monday, emotionally drained investigators once again returned to the assumption that Pearl remains alive, in a case that has now expanded to other major cities.

Senior law enforcement authorities said Sunday that they have fully discounted the e-mail received Friday, which at first seemed like a credible death announcement.

“We believe Mr. Pearl is alive,” said Syed Kamel Shah, inspector general of police for the region that includes Karachi. “We are making headway in our investigation.”

Still, after searching hundreds of graveyards in the city three times over, seizing computers and rounding up suspects ranging from an Islamic cleric to teenage pranksters, authorities remained mystified about the fate of Pearl, the South Asia correspondent for the Wall Street Journal.

On Sunday, they expanded their dragnet to the capital, Islamabad, and its environs, where they made several raids and detained suspects for questioning.

Ten people were believed to be in police custody Sunday.

A senior police source in the Islamabad area said the search had expanded to all of Pakistan, and particularly to the loosely governed areas bordering Afghanistan.