Updated

Yemeni interrogators suspect the man accused of killing three American missionaries at a Baptist hospital may have ties to Al Qaeda, officials said Tuesday, and U.S. investigators joined the search for those behind the murders.

Two of the slain Americans were buried Tuesday in the southern Yemeni town of Jibla, where each had worked for more than two decades and where the attack took place. The third was to be flown to the United States.

The sole survivor of Monday's shootings, pharmacist Donald W. Caswell, 49, of Levelland, Texas, left the hospital Tuesday after recovering from wounds in the abdomen, a U.S. diplomat said, speaking on condition of anonymity.

The other Americans who worked at the hospital have been taken to the capital with Caswell in U.S. Embassy vehicles, the diplomat said.

An FBI team arrived Monday in Jibla and worked overnight. The American diplomat would not say whether U.S. investigators were being allowed to directly question the suspect arrested for the slayings, but said the Americans "are very close" to the interrogation.

In past investigations of attacks on Americans here, Americans working alongside Yemenis have complained of having limited access to suspects.

The U.S. Embassy said it was too early to tell if terrorism was behind Monday's shootings at a Southern Baptist hospital. But Yemeni Prime Minister Abdul-Kader Bajammal included the slayings in a list of terrorist acts he presented to parliament later in the day.

Bajammal accused "extremist elements in several (Yemeni) parties of having links with Al Qaeda." He did not elaborate.

Officials close to the investigation said Yemeni interrogators have strong suspicions the accused gunman has connections to Osama bin Laden's terror network. Yemen is bin Laden's ancestral homeland and has been a fertile recruiting ground for him.

Yemen has been a key front in the U.S.-led war on terrorism and its government signed on as Washington's partner after the Sept. 11 attacks.

In the attack, the gunman slipped past security at Jibla Baptist Hospital, 125 miles south of the capital San'a, cradling his hidden gun like a baby. He entered a room where the director was conducting a meeting and opened fire at about 8:15 a.m. Monday, officials and witnesses said.

After shooting three people in the head, killing them instantly, the gunman headed to the pharmacy and shot the pharmacist in the abdomen. Yemeni authorities arrested a Yemeni suspect they identified as 30-year-old Abed Abdul Razak Kamel.

The International Mission Board of the Southern Baptist Convention identified the dead as purchasing agent Kathleen A. Gariety, 53, of Wauwatosa, Wis.; Dr. Martha C. Myers, 57, of Montgomery, Ala.; and hospital director William E. Koehn, 60, a Kansas native who moved who moved to Yemen in 1975.

Myers — who had worked in Yemen for 24 years — and Koehn — who had planned to retire next October after 28 years at the hospital — were buried in a missionary cemetery on the hospital grounds Tuesday, Yemeni police said.

The hospital complex, surrounded by police and machine-gun mounted police cars since the shooting, was closed to outsiders. Townspeople, unable to attend the burial, gathered at the hospital gates.

"Today was very sad for all of us, and what made it even more sad was that we couldn't participate in the burial," said Malka al-Hadhrami, a Jibla resident who said she had worked as a clerk for Myers for 18 years.

"All Jibla weeps for them," al-Hadhrami said, choking back tears.

Pharmacist Donald W. Caswell, 49, of Levelland, Texas, was recovering from surgery, his father said.

The 80-bed Jibla hospital, which sits on a hilltop amid trees, treats more than 40,000 patients annually, providing care free to the poor. Hospital officials said the staff included 64 foreigners, including 25 Americans.

President Ali Abdullah Saleh condemned the shootings as "criminal and disgraceful" in a message to President Bush and said Yemen would "strengthen our determination to eradicate terrorism," the official news agency Saba reported.

Investigators also were questioning prisoners picked up in earlier sweeps of suspected Muslim militants to see what they knew about Kamel. The suspects included some believed linked to Al Qaeda and some to a small Yemeni group known as al-Jihad.

Al-Jihad, which attracted many Yemenis who had fought the Soviets in Afghanistan, had chiefly targeted secular figures from once-socialist southern Yemen. It had not been active for several years.

Earlier, officials had said Kamel claimed to have ties to a group plotting attacks on foreigners and secular-minded politicians.

Kamel told interrogators that he staged the attack in collaboration with Ali al-Jarallah, who was arrested for shooting dead a senior Yemeni leftist politician on Saturday, Saba reported.

In his report to parliament, Prime Minister Bajammal included the Jibla shootings among 15 "major terrorist acts" in Yemen since 1997. Others included the Oct. 6 suicide bombing of a French oil tanker Limburg off the coast of Yemen and a similar suicide bombing of the USS Cole off Yemen in October, 2000. Both ship attacks were blamed on Al Qaeda, also held responsible for the Sept. 11 attacks.

"Terrorist acts, in particular the attack on the USS Cole and the Limburg tanker, resulted in enormous material and moral damage which have tarnished the image of our country and made it appear a fertile land for terrorism and terrorists," the prime minister said.

Anti-American sentiments are running high in the Middle East due to perceived U.S. support for Israel and the standoff with Iraq.