BERLIN » The man German security officials call a major security risk looks like a figure from a rap video, especially with the tattoos on his hands. The right one says "STR8," and the left one "Thug."

"This is from the days when I lived the life of an unbeliever," said the man, Denis Mamadou Cuspert, as he clenched his fists and looked at the tattoos. "Allah will erase them from me one day."

Cuspert, once a popular rapper in Germany, today is one of the best-known singers of nasheeds, or Islamic devotional music, in German. Security officials say, though, that he is an influential figure who incites violence and unrest through inflammatory videos and fiery speeches that praise terrorists and attack the West.

German authorities say people like him inspired the fatal shootings of two U.S. airmen at the Frankfurt airport in March. The 21-year-old man accused of the killings, Arid Uka, whose trial began in Frankfurt on Wednesday, has said he opened fire on a busload of U.S. service members after seeing a video that claimed to show Muslim women being raped by men in U.S. military uniforms. U.S. officials have said the video — which Cuspert, 35, acknowledged posting on his Facebook page, and which Uka copied — was staged by militants.

Uka said he was listening on his iPod to nasheeds calling for opposition against occupation forces and the West as he traveled to the airport just before the shootings.

"It made me really angry," Uka told the judge Wednesday, referring to the songs’ lyrics.

During a tearful confession, he said that Islam had given him strength after a period of depression, but that he now realized that "I have damaged my faith."

German terrorism investigators see Cuspert as a threat who provokes young people angered by what they see as a Western campaign against Islam; some even likened him to Anwar al-Awlaki, the U.S.-born preacher now in hiding in Yemen who is also accused of promoting violence through speeches and videos.

"After establishing rapport through music, he introduced radical ideology to an audience already receptive to him," said Raphael F. Perl, who runs the antiterrorism unit for the Organization for Security and Cooperation in Europe.

In an interview at a mosque here, Cuspert denied any direct connection to Uka, although he said he supported his actions.

"The brother hasn’t killed civilians," he said. "He has killed soldiers who had been on their way to kill Muslims."

That is similar to the message in videos posted on YouTube and jihadi websites that have made Cuspert popular among al-Qaida supporters in Europe and elsewhere. As evidence of his reach, a man who goes by the name of "Abu Bilal" in the tribal areas in the Afghanistan-Pakistan border region said of Cuspert: "The brother’s voice has reached the hearts of many people here, too."

Cuspert gives speeches all over Germany, and young people are drawn to elements of his personal story, including his membership in Berlin street gangs — he said he used to be a "real bad boy" — and the notion that he finally found the "right way."

Cuspert says that Shariah, the legal code of Islam based on the Quran, permits self-defense.

"My duty is to use my voice for telling people the truth, and the truth is, jihad is a duty," he said.

Security officials say that young people who are clicking on his videos do not realize that what they are listening to has been inspired by a radical jihadist theology based on the fundamentalist Salafi branch of Islam.

In his speeches, Cuspert has expressed outrage over U.S. drone strikes in Pakistan’s tribal areas, Yemen and Somalia, and has said that his biggest wish right now is the death of President Barack Obama, who he said was an enemy of Islam.

Suspecting that Cuspert was planning to join his friends in Pakistan, German authorities in July demanded that he surrender his passport. "I told them that I had lost it," he said.

So far, the authorities say, they have not had enough evidence to arrest him for his speeches, but they are trying to put him behind bars for offenses they say he committed during his former life as a rapper.

On Aug. 18, Cuspert was tried here on illegal weapons possession charges. Prosecutors said that he held a gun in a video and that the police found rounds of ammunition during a search of his apartment. German security officials said they sought to jail Cuspert and stop his "video propaganda for jihad." The trial judge convicted Cuspert but spared him a prison sentence, ordering him to pay a fine of 1,800 euros, about $2,600.

Before he took his new name, Abou Maleeq, Cuspert had another life. He was born and reared in Berlin by his German mother. His father, who was from Ghana, left the family when Cuspert was a baby. When conflicts increased at home with his stepfather, a former U.S. Army soldier and strict disciplinarian, Cuspert was sent to a home for difficult children. After five years, he returned home.

"I grew up with racism," Cuspert said. "Though my mother is German, some teachers back then would call me ‘Negro’ and treat all Muslim kids bad."

His argument with U.S. foreign policy grew in 1990 in the months leading up to the first Persian Gulf war, and he joined demonstrations in Berlin.

"We marched, shouted and burned the American flag," he said, smiling.

In 1995, he found a new outlet for his anger: as the rapper "Deso Dogg." He said, "My songs were about the time in prison, racism, war."

His music career soared. He went on tour with rappers like DMX and worked on the soundtrack for a German film. But after surviving a car accident, he started questioning his lifestyle and turned to Islam for answers. In 2010, he ended his career as a rapper and turned his focus to fighting the United States and the West.

The message on his cellphone’s voice-mail system makes no secret about his ultimate aim in life.

"The martyrdom is the most beautiful," he says in his recording. "Allah is the greatest."