In his last conversation with his sister in Somalia, Dr. Mohamed Aden Ali spoke as the protective older brother.

"Be careful," he told her softly over the phone.

Seven hours later, Qamar Aden Ali, his kid sister and Somalia's minister of health, was dead, one of 24 people killed by a suicide bomber at a graduation ceremony for medical students. Her death and talk that Ali may be asked to succeed her as Somalia's health minister puts him at an emotional crossroads: Should he stay safe in Minneapolis or go back to Somalia and take up his sister's cause?

"The choice of taking this risk is very high," Ali said. "I can decide only after I go to Somalia."

Ali has not seen his native Somalia since 1993, when he returned to help his mother flee the civil war. A surgeon in Somalia, he built a comfortable life in the Twin Cities as the head of a home health care agency and the chief executive officer of the Somali Health Professionals Association.

For now, he's intent on going to Somalia for just two to three weeks to take part in family ceremonies to remember his sister. Unless, he says, something changes his mind.

Growing up in Mogadishu, he and Qamar were like twins, he says. They were just one year apart.

They were together always, playing and fighting as siblings do. But if anyone else laid a hand on his sister, he would step in to protect her.

Sometimes when Ali would head out for a soccer game, Qamar would grab onto him, clutching at his clothes to try to make him stay, he said.

The memories brought a smile to his face Friday in his south Minneapolis office as he talked proudly about his sister's legacy.

Qamar was born in a small village west of Mogadishu, the third of 11 children. She graduated from college in Somalia and traveled to then-East Germany to study political science. Later, she went to London to attend law school and became a lawyer.

Though she became a British citizen, she returned to Somalia in the mid-1990s at a time when others were fleeing the erupting violence. She wanted to help her country, Ali said.

She participated in negotiations with warlords to keep the peace and was chosen in 2004 as Somalia's minister of health.

In that post, she paid particular attention to helping to find shelter for people living in the refugee camps and promoting health services for the displaced and diseased, he said.

"This was her work. She gave her knowledge to the country."

Shock waves in Minneapolis

When he goes back to honor her memory, Ali will find a country ravaged by an even more brutal war than the one he left.

To date, no one has claimed responsibility for the suicide attack that killed 24 people including his sister, two other government ministers and a number of medical school graduates.

Though there have been suicide bombings in Somalia before, this one was considered especially heinous because of where it happened and who was there.

Doctors are seen as Somalia's best hope for the future. The killing of the medical school graduates provoked the first known protests against the insurgent group Al-Shabaab, the group believed to have recruited about 20 young Minneapolis men of Somali descent to fight in Somalia. Six of the young men who left reportedly have been killed.

The graduation ceremony bombing was denounced in a demonstration in Minneapolis last weekend organized by a new group called Save Somalia Today and attended by at least 100 local Somalis.

The U.S. State Department has identified Al-Shabaab, which means "the youth" in Arabic, as a terrorist group, and says some of its leaders have ties to Al-Qaida leaders.

Although no group has claimed responsibility for the bombing, the government of Somalia said it was the work of religious extremists, and a top Somali government official said the bomber was a Danish citizen of Somali descent.

It seems another movement is now afoot, this one driven by Somalis returning to their homeland to help build a new government instead of overthrowing it.

'Nobody was expecting this'