Fayetteville, N.C. - A Fort Bragg soldier charged with first-degree murder in the death of his wife took an anti-malaria drug linked to aggression and suicidal thinking while serving in Afghanistan, and allegedly killed his wife just weeks after his return.

A second soldier suspected of killing his wife had almost certainly been given the drug, Lariam, in Afghanistan, according to an Army medical source familiar with the soldier's duty there.

The attorney for Master Sgt. William Wright confirmed Friday his client took Lariam, also known by the generic name mefloquine. "He was taking it," Thomas Maher said. Maher said his client didn't attribute any particular adverse effects to the drug, but "he felt like he was kind of floating when he got back" from Afghanistan.

Wright, a special operations soldier in the 96th Civil Affairs Battalion, strangled his wife, Jennifer, at their Fayetteville home on June 29, then buried her body in a shallow grave, according to authorities.

The second soldier, Sgt. 1st Class Rigoberto Nieves, a Green Beret, shot and killed himself after shooting his wife, Teresa, in their Fayetteville home June 11, two days after returning from Afghanistan, police said.

It is unclear if a third soldier, Sgt. 1st Class Brandon Floyd, 30, who served in Afghanistan from November to January as a member of the secret counterterrorism unit called Delta Force, took Lariam, but Army troops in Afghanistan and other malarial countries are routinely prescribed it. Floyd shot his wife, Andrea, in their home in Stedman, near Fayetteville, on July 19, then shot and killed himself, authorities said.

Lariam has been blamed for psychotic episodes and suicidal behavior for more than a decade. The official product information sheet, written by manufacturer Hoffmann-La Roche and approved by the U.S. Food and Drug Administration, states Lariam has been associated with aggression, paranoia and suicidal thoughts.

It is the Army's drug of choice to prevent malaria, which is endemic in Afghanistan from May to November in all but mountainous central and northeast regions. The Army's Walter Reed research institute developed the drug, which was cleared for use in the United States in 1989. For most who tolerate it well, Lariam is considered highly effective at preventing malaria.

Official Army spokesmen would not say whether any soldiers involved in the shootings had taken Lariam, citing the ongoing investigation. The state medical examiner's toxicology report on Nieves said only that there was no alcohol in his system. A spokesman said no other toxicological tests were performed.

Army officials have said it is unlikely Lariam played any role in the recent episodes of domestic violence because one of the four suspects did not serve in Afghanistan and one had been back in the United States for seven months, making a connection to the drug unlikely. In the fourth case, Sgt. Cedric Griffin, an Army cook, stabbed his estranged wife to death in her trailer "at least" 50 times and set her body on fire July 9, authorities said. He had not been deployed. He is charged with first-degree murder.

In a statement late Friday, the Army said it will "investigate potential explanations for the recent spouse murders/murder-suicides at Fort Bragg.

"This includes a medical literature search on effects of the use of mefloquine/Lariam, although there is no evidence indicating its possible use had any impact on the behavior of the suspects."

Fort Bragg officials said earlier in the week the initial investigation would focus on possible marital difficulties between the suspects. The Pentagon is set to send a team to Fort Bragg to review military policies and programs related to the killings, said Maj. Gary Kolb, spokesman for the Army's Special Operations Command. Kolb said the deaths did not appear to have been foreshadowed by a pattern of domestic violence.

About 80 percent of domestic killings are preceded by an increasing level of domestic violence, according to Debby Tucker, co-chairwoman of the Defense Department's task force on domestic violence and co-founder of the National Training Center on Domestic and Sexual Violence in Austin, Texas. She said the military should consider all factors that could have contributed to the killings, including any drug that can alter behavior.

A UPI story published July 30 reported scores of Peace Corps volunteers are reporting that over the past 12 years they suffered paranoia, anxiety, hallucinations, memory loss and suicidal behavior they blamed on Lariam. UPI earlier reported evidence the drug can cause mental problems so severe that in a small percentage of cases it has triggered suicide. Thousands of pages of internal Roche safety documents obtained by UPI showed the company tracking suicides and suicidal behavior and acknowledging depression as a side effect.

A Canadian government official who has investigated a murder-suicide attempt that he believes is related to Lariam also called for the Army to look at the drug's possible role. "Given my experience investigating Lariam, it would seem to me it would be worth investigating," member of Parliament John Cummins said in a telephone interview. He has studied reports of Lariam side effects among Canadian soldiers in the early 1990s, including the 1994 suicide of army Cpl. Scott Smith, who was stationed with the United Nations peacekeeping mission in Rwanda. Smith reported having hallucinations he attributed to Lariam before he shot himself.

The U.S. Labor Department has awarded two Peace Corps volunteers workers compensation for Lariam-induced psychoses - one lasting three days, the other an entire year.

And during the Somalia operation in the early 1990s, a Canadian army corporal, Clayton Matchee, allegedly tortured and killed a 14-year-old boy who had sneaked into the compound. Matchee subsequently attempted suicide by hanging and suffered permanent brain damage. His wife, Marj, told a Canadian newspaper at the time when her husband was home from Somalia on leave before the incident, she woke up in the middle of the night to find his hands around her neck. Marj Matchee said her husband attributed his behavior to Lariam. A formal inquiry concluded no link to Lariam "without extensive further investigation."

U.S. Army officials said they never saw any problems among U.S. soldiers taking Lariam in Somalia. The activist group Lariam Action said that it has been contacted by 120 veterans of Somalia who said they continue to have problems with the drug, including 11 who said they have considered or tried suicide.

Freelance writer J.S. Newton contributed to this story.