A Muslim advocacy group on Monday plans to announce a $10,000 reward for information leading to an arrest of the gunman who killed a New York mosque leader and his associate as the families of the slain men make funeral arrangements and continue their quest for answers in the shooting.

Imam Maulama Alauddin Akonjee, 55, and Thara Uddin, 64, were both shot in the head near the Al-Furqan Jame Masjid mosque in the Ozone Park neighborhood of Queens as they left afternoon prayers on Saturday in their traditional religious attire, according to police.

“He always wants peace,” Akonjee’s son, Naim Akonjee, 21, said of his father through tears. “Why did they kill my father?”

Another son, Foyez Uddin, who isn’t related to the other victim, told The Associated Press in Bangladesh that his father and mother had booked flights for Aug. 31 to visit Akonjee’s mother. The son said the family is discussing funeral plans. He said they “cannot believe he is no more,” call the loss “irreparable.”

The Council on American-Islamic Relations, or CAIR, planned to announce on Monday a $10,000 reward for information leading to the arrest and conviction of the shooter.

Police said they have not yet determined a motive for the killings, but some in the Bangladeshi Muslim community served by the mosque worry it could be a hate crime.

Monir Chowdhury, who worshipped daily with the two men, said he had moved to the community because of its large Bangladeshi immigrant population, but in recent months has been harassed by people shouting anti-Muslim epithets.

In one incident, a man called him “Osama” as he walked to the mosque with his 3-year-old son. With the killer still on the loose, Chowdhury decided it would be best to drive to prayer services.

“A lot of neighbors said, ‘Hey, don’t take your kid with you,'” he said. “People, they just hate us.”

Police on Sunday released a sketch of the suspected gunman, a dark-haired, bearded man wearing glasses. He was described by witnesses as a man with a medium complexion. A person who lives near the shooting scene shared with The Associated Press and other media organizations surveillance video that showed a man walking up behind the imam and his associate, shooting them and then walking off. Police said they were reviewing the video.

In a statement on Sunday, New York City Mayor Bill de Blasio, a Democrat, said the slayings were felt by all of New York City.

“While we do not yet know the motivation for the murders of Maulama Akonjee and Thara Uddin, we do know that our Muslim communities are in the perpetual crosshairs of bigotry,” the mayor said. “It remains critical that we work to bridge the divides that threaten to undermine the greatness of our city and country.”

An official with the government in Bangladesh condemned the killings on Twitter. The country’s State Minister for Foreign Affairs, Mohammed Shahriar Alam, called the shooting a “cowardly act on peace-loving people.”

The U.S. Ambassador to Bangladesh, Marcia Bernicat, also decried the violence, saying Akonjee “stood for peace.”

Several police officers were stationed outside the mosque on Sunday as worshippers remembered the victims and remarked on their devotion to their families and faith.

On Monday, Muslim community members will gather in Brooklyn to hold Islamic funeral prayers for the two men.

(AP)