NAIROBI, Kenya (CNN) -- A radical Islamic cleric who faced charges relating to terrorism was killed in a daylight ambush Monday morning in Kenya's main coastal city, Mombasa, Kenya Police said.

Aboud Rogo Mohammed was accused supporting Al-Shabaab militants in Somalia and was blacklisted by the United States and U.N. Security Council. He also faced charges before a Kenyan court for planning terror attacks in Mombasa

"We have received reports that Aboud Rogo Mohammed has died," said Eric Kiraithe, the Kenya Police spokesman. "We are taking this matter very seriously. It is disappointing to us, because we had a case in court and we had evidence to go to its logical conclusion."

But Rogo's wife, Hania Said, claimed the shooters were Kenyan police.

Kiraithe dismissed that claim and asked for the public to give the police information.

"That can only be nonsense," he said. "For what conceivable reason would that happen? What we need is for everyone to cooperate without any fear. We have a witness protection program now."

Rogo's wife said the cleric was traveling with his family in a van on the Mombasa-Malindi highway when they were ambushed by a group of men who shot her husband more than a dozen times.

She said she was shot in the leg and Rogo's father was shot in the hand.

Their van, a 14-seat white Nissan, was riddled with bullets and splattered with blood. Police tried to take away Rogo's body, but a group of supporters refused and took it away to be buried in the Muslim public cemetery.

The shooting sparked protests by Mombasa's Muslim community. Anti-riot police responded with tear gas. A government vehicle was burned near a mosque where Rogo once preached.

A U.N. report in July said that Rogo "threatened the peace, security, or stability of Somalia, by providing financial, material, logistical or technical support to Al-Shabaab."

It went on to claim that he was a key recruiter of Kenyan Muslims to fight with Al-Shabaab, the al Qaeda-linked militant group that is trying to overthrow the Somali government.

Journalist Bihoff Mukoto contributed to this report.