Kenyan police and relatives said Thursday they have found no sign of prominent journalist and controversial blogger Bosire Bogonko, one year since he mysteriously disappeared.

Kenya began emotional commemorations on Tuesday to mark the first anniversary of Nairobi's Westgate mall massacre, remembering the 67 people killed by Somali Islamist gunmen and those who risked their lives to stop them.

In a speech at a memorial site opened at the capital's National Museum, First Lady Margaret Kenyatta said the east African nation had been "seriously scarred" but not broken by the attackers from the Al-Qaida-affiliated Shebab rebels.

Three German men were arrested at the weekend when they flew home from Kenya, accused of having joined and fought with Somalia's Shebab Islamist militant group, officials said Monday.

Kenyan police on Wednesday produced a small arsenal of weapons recovered after last year's Westgate mall massacre, in the ongoing trial of four men accused of helping the gunmen.

The slow moving trial in Nairobi -- which opened in January -- has heard evidence from people who were at the mall when the gunmen from Somalia's al-Qaida-linked Shebab launched their attack in September 2013, killing at least 67 people.

Kenya's internationally funded anti-terrorism police have carried out a series of killings and "enforced disappearances" following a string of attacks in the country, Human Rights Watch said Monday.

"Kenyan counter-terrorism forces appear to be killing and disappearing people right under the noses of top government officials, major embassies, and the United Nations," said HRW's deputy Africa director Leslie Lefkow.

Kenya is closing its borders to travelers from Guinea, Liberia and Sierra Leone, the three countries worst hit by the Ebola outbreak, the government said Saturday.

Kenya Airways also announced that it would suspend its flights to Freetown and Monrovia when the government travel bar on passengers comes into effect on Wednesday.

Kenyan detectives told a court Thursday they had lost the trail of British terror suspect Samantha Lewthwaite, known as the "White Widow", suggesting the fugitive may have taken another identity.

Detectives hunting Lewthwaite were ordered to appear in court Thursday in the port city Mombasa after failing to heed previous summons to provide updates on their search.

Three women were arrested Wednesday, in the United States and Netherlands, for allegedly giving financial help to Somalia's al-Qaida-linked Shebab, authorities said.

Since the United States deems the group a terrorist organization, such aid is a crime for which Muna Osman Jama, 34, was arrested at her home in Reston, Virginia, the Justice Department said in a statement.

At least four people were killed in the Kenyan coastal city of Mombasa on Sunday in an attack by armed men on a motorbike, according to medical sources.

Another eight people were wounded in the shooting, said the same source.

Somalia's al-Qaida-linked Shebab on Saturday claimed an attack on a bus near the Kenyan vacation island of Lamu in which seven people were killed.

The Kenyan Red Cross said five civilians and two police officers died late on Friday when armed men opened fire first on a bus, then on a car and a police vehicle, near the town of Witu, 50 kilometers (30 miles) from Lamu island.