DUBLIN, Ireland They moved in lockstep, nearly 400 of them, to the rhythms of a drummer and a piper. They marched a half-mile through downtown streets in the Irish capital, on their way to the U.S. Embassy.

The straight-lined formation of former Irish soldiers, three abreast and capped with the blue berets of the United Nations peacekeeping forces, marched with purpose. On this day, July 5, they wanted the U.S. to finally, after 34 years, bring to justice the man they say murdered two of their comrades.

In 1980, Derek Smallhorne and Thomas Barrett of the Irish Defense Forces were kidnapped, tortured, shot and killed, rare casualties of a U.N. mission to keep the peace among warring factions in Lebanon. A third Irish private, John O'Mahony, was shot twice but survived and helped lead the march.

The marchers say one man did this, a man who lives now in Michigan. His name is Mahmoud Bazzi a Lebanese native who is now 71 and makes a living selling ice cream in Dearborn, Mich.

Two eyewitnesses O'Mahony and a former journalist who is American link Bazzi to the crime. On July 15, U.S. Homeland Security officers arrested Bazzi at his apartment in east Dearborn. This week, he is due in federal court in Detroit, where the U.S. plans to start the process of deporting him to his native Lebanon.

The government is holding him on an immigration violation. Bazzi used someone else's passport to enter the country 21 years ago. U.S. authorities won't say whether he will face charges linked to the shootings.

But "the allegations of what happened in Lebanon factor heavily in our investigation and our efforts to remove him," Khaalid Walls, spokesman for the Detroit office of U.S. Immigration and Customs Enforcement, said Friday.

Families of the dead soldiers welcomed the arrest, but they want more. They want Bazzi tried for war crimes.

"I don't think any of the families are asking too much," said Derek Smallhorne Jr., who was 9 when his father was killed. "Do the right thing. ... There has to be enough evidence there."

But Bazzi told the Free Press that the evidence including a confession he made on TV long ago in Lebanon is not what it seems.

He is innocent, he said.

Tensions were high on April 18, 1980, even for south Lebanon. But John O'Mahony wasn't worried. In days, he'd be headed home to Killarney, a tidy tourist town flanked by mountains in southwestern Ireland. Things were looking good.

As a soldier for UNIFIL, the United Nations Interim Force in Lebanon, O'Mahony spent considerable time in dangerous areas. UNIFIL helped transport soldiers and supplies to several checkpoints and observation posts in territory controlled by a hostile Christian militia. O'Mahony was a driver.

But not today. Recent events had led to death threats specifically to Irish troops. O'Mahony heard he wouldn't be taking any risky trips, and he told his friend, the quartermaster, that was just fine. He'd gladly stay back in the safer U.N. zone.

"I said to Paddy, 'You know, Paddy, I'll have a good chance of going home alive,' " O'Mahony said. "There was nobody allowed in behind the lines, you see."

But early on that same morning, O'Mahony received new orders. The farthest outpost in the south Maroun al-Ras, located on the Israel border needed new supplies. Indeed, O'Mahony would be driving once more into hostile territory.

"My reaction? My face dropped," O'Mahony, now 62, said in a recent interview at his home in Ireland. "I had the premonition that this was trouble. Serious trouble."

Lebanon roiled with civil war at the time. And two years earlier, after Israel was attacked, its military pushed into the country, invading from the south to drive Palestinians from its border. The United Nations intervened and pressured Israel to withdraw. But Israel had a surrogate the Lebanese Christian militia that controlled a buffer zone extending several miles north of the border. The militia could help keep the Palestine Liberation Organization away from Israel. And in the middle of these warring factions, the UN installed its peacekeeping force.

O'Mahony had been in Lebanon for six months. Growing up on a farm, O'Mahony joined the reserve forces at 13. He first donned a military uniform in 1966.